6 ms·

For those who are thinking "Yeah, duh, just use an image editor to crop it," as I did at first, this article is probably most useful for barely-tech-literate pe

For those who are thinking "Yeah, duh, just use an image editor to crop it," as I did at first, this article is probably most useful for barely-tech-literate people, who can use Microsoft Word, Outlook, Edge, maybe Teams, and not much else. They wouldn't think that they'd need to open a whole separate image editor when Word has a cropping function built in that's always worked for them before.

tjoff 4y ago
Not foolproof, there have been instances when people have been cropping in an image-editor and failed to realize that the thumbnail hadn't been updated and leaked information.
- a_shovel 4y ago
  Okay, that one might catch me. I couldn't tell if an image had a thumbnail stored with it to begin with.
- Hamuko 4y ago
  If I need to ensure there's nothing on an image that wasn't supposed to be there, I just copy the visible pixels and paste it to a new document. No EXIF data, outdated thumbnails or anything.
  - e28eta 4y ago
    I can actually imagine a tool that’d copy/paste the metadata along with the data, but I don’t know if any exist.
    - chihuahua 4y ago
      Using a screenshot tool should be safe. It will treat all pixels on the screen the same, so it doesn't know that some pixels have metadata beyond what's visible on the screen.
      - hef19898 4y ago
        Then print and scan the screen shot before faxing it to authorities.
        toss1 4y ago
        And make sure that the scan is of low enough resolution that it fails to pickup the printer identification dot pattern in the printout... The fax should help with that, except that it'll reveal the location of your source fax. Using fax software/service needs its own security... maybe snail-mail... This is getting seriously nontrivial
        adolph 4y ago
        Don’t forget to pilfer newspapers from around the country and cut/glue letters from different fonts to compose the message and use homemade paper as the base layer.
        hef19898 4y ago
        Instead of home made, use the most prolific paper you can imagine!
        hef19898 4y ago
        Well, if we talk about goverbment whistleblower programs I assume using a fax from a random location while travelling would be good enough to not be identified by your employer (or whom ever you blow whistle on). If you do blow the whistel on the government, well, you better trust your journalist partner a lot. Or use a trustworthy lawyer as a go between. But hey, one could send the fax back and forth, cut of the fax numbers and physically mail it from a very busy train station! And have a someone put the letter into the letterbox for you, someone you pay out of view of any CCTV cameras!
        gregoryl 4y ago
        People who have information x, and were in location y (especially where y is not a common place for x holding people) will be a very limited set.
- hilbert42 4y ago
  "...failed to realize that the thumbnail hadn't been updated..." Right, I'd never use part of the original image. Best print it out and rescan it, preferably on different scanner. Being truly anonymous is enormously difficult, even the Bauer pattern/Bayer filter shape in one's image sensor will give one away. That alone requires sophisticated filtering to decouple it from a specific sensor/camera. And that's only the beginning, there are many other factors that contribute to the leaking one's identity.
  - acuozzo 4y ago
    > Best print it out https://en.wikipedia.org/wiki/Machine_Identification_Code https://en.wikipedia.org/wiki/Machine_Identification_Code
    - jwestbury 4y ago
      Black and white from here on out, then.
      - hilbert42 4y ago
        Right. Good idea, see my 2nd comment.
    - hilbert42 4y ago
      I'm aware of that, hence my comment about the many other issues that have to be considered in decoupling information from hardware. 1. First, most whistleblowing comes from B&W documents so color isn't an issue. If it is the case then there are alternative solutions which I'll not persue here in any detail (the post would be very long). 2. Printing then rescanning can decouple the camera to some extent as physical distortions are introduced by (a) the geometry of the inkjet nozzles or laser subsystem, (b) more geometric distortion is added by changes in paper size as its fused/dried, (c) additional distortion is added by the optics of the rescanning system, same goes for any further printing and so on. Also, each stage alters the gamma and adds other non linearities to the transfer. 3. Reducing the scanning resolution will add additional distortions, blurring is to be encouraged but not to the point of illegibility. (Doing a low resolution copy on a FAX machine with time/date/headers/footers turned off could help.) 4. This may sufficiently decouple the camera but it won't decouple the copying/scanning/rescanning equipment. Best do this on machines that are located well away from the source so they're not easily traceable or associated with you or your work. 5. Copying documents across multiple different photocopiers will help as they all add optical and other geometric distortions and transfer—gamma-type—errors. Deliberately lightening and darkening the image at each stage will further increase distortions. The combined distortions will make it very difficult (but not impossible) to reverse engineer the path back to the source. Have you ever wondered why the quality of the printed type in copies of evidence, FOIs, official documents etc. often looks so daggy and blurred as to be almost illegible? 6. The idea is to add as much distortion and blurring in the chain of copies as is possible and yet still keep the final copy legible/identifiable. It's a fine balance. 7. That still does not guarantee anonymity. Sensitive documents are often 'doctored' so that each recipient receives a subtlety different copy, spacing between words may change so may the page layout, also small seemingly insignificant and barely obvious 'marks' on the page will differ between copies thus identifying each recipient. None of the camera techniques above will overcome this problem. 8. One technique is to retype the document so that it is almost identical in both looks and content but with lots of subtle changes in both layout and wording—but NOT to the extent of changing the document's meaning. Same goes for modifying images (a complex matter). As a last resort this could give you a degree of plausible deniability in cases where marked documents are issued. If you do this it would be very advisable to spirit away actual copies of the originals in a truly safe location—you may really need them one day (after you're accused of, say, forgery). I'd suggest you only go down this path if you are very competent and the stakes are very high. 9. None of what I've said should be taken lightly. No matter how hard you try to decouple yourself totally from the source (or from any involvement) it is nigh on impossible to hide from formidable and sophisticated forensics if applied relentlessly. 10. Moreover, whistleblowers, more often than not, end up being reveilled by fellow workers and usually without a job or decent reemployment prospects. Unfortunately, our culture hasn't embraced whistleblowers and whistleblowing as it should. It's a very risky business. Take the case of whistleblower Daniel Ellsberg and the Pentagon Papers; his effort wasn't rewarded as we ought to expect and he nearly ended up being locked up. Moreover, at one point Ellsberg wistfully noted that reaction by the American public to his efforts wasn't very favorable. When it comes to whistleblowing it seems not much has improved in the last five decades. _ Edit: FYI, there are many excellent videos on Daniel Ellsberg and whistleblowing on YouTube.
- knodi123 4y ago
  Referring to TechTV presenter Cat Schwartz, I presume? https://en.wikipedia.org/wiki/Catherine_Schwartz https://en.wikipedia.org/wiki/Catherine_Schwartz
- 8n4vidtmkvmk 4y ago
  i just screenshot images. that way it'll lose any metadata. any parts outside of my screenshotted area can't be included... and i think the black rectangles are genuinely black in sharex...
kerblang 4y ago
I think I would do this by default because I'm so ignorant/incompetent with the fancier tools that I'd never think to look for a cropper. I'm the cretin that says, "Oh I can do this in MS Paint!" and even spends a 1/2 hour remembering how to do that much...
deleted 4y ago
[deleted]
bcrosby95 4y ago
Iirc some formats support cropping too. So even if you crop in an image editor, all the data may still be there.
SapporoChris 4y ago
I sometimes get smartphone photos of computer screens sent to me by friends. It makes me cringe every time, but now I'm thinking maybe they're onto something.
- c0nsumer 4y ago
  While I doubt they are meaning it as such, it's not far off from the technique of physically redacting a printout and then scanning that as duotone so there was never, ever a digital path between the original and the resulting digital copy.
- LarryMullins 4y ago
  I believe this is often done to avoid corporate surveillance on the computer that might record the screenshot and exfiltration.
  - thrashh 4y ago
    I think it’s usually done because copying a file from a computer to a smartphone universally is still a pain in 2023 - Bluetooth file transfer… I don’t even know where to begin - AirDrop requires you to be in the Apple ecosystem. I think default settings also require you to be logged in the same Apple account on both devices too - Cloud storage services need you to install the app or login into the website on both your phone and the computer with the same account. Very few of my non-tech friends even have any cloud storage service outside what their phone uses Ngl, I take photos of my screens sometimes
    - albert_e 4y ago
      some other methods that work well in some cases: whatsappweb opened in a browser pushbullet google photos / Gmail to yourself
    - teo_zero 4y ago
      Attach the file to a draft email that you save without sending. You'll find it in the draft folder on both the computer and the phone.
burkaman 4y ago
> barely-tech-literate people I think this is a little unfair. I would not blame anyone for thinking that the part of the image they cropped is deleted. That's what the word means, that's what it looks like is happening, there's usually no warning that it's recoverable. When you delete text it is really gone from the document, even though you can undo to get it back. It's totally reasonable to expect images to work the same way.
- a_shovel 4y ago
  What I had in mind when I was writing that was a story I once read of a user who did all of her computer interactions through Word (i.e. all of her emails were empty with a Word document attachment containing the text, among a few other amusing anecdotes). But yeah, the characterization is a bit unfair from that perspective.
  - alpaca128 4y ago
    I know a few people personally who mainly used Word (and increasingly also web browsers) when working on computers, and it's sometimes obvious they view everything a computer does through that lens. For some people only used to Windows even appstores are a foreign concept, a relative's first impulse when trying to install a phone app is to open the phone's web browser and do a Google search. Those are things many recent UI "improvements" haven't considered.
- heavenlyblue 4y ago
  Arguably even undo is probably now saved in the documents themselves.
- wolrah 4y ago
  OP isn't saying the person is barely tech literate because they didn't expect the image to be restorable, but that they're likely barely tech literate because they were using a word processor as an image editor. Abusing Microsoft Office applications to do things they're not designed to do has sort of a bathtub curve of likelihood versus tech literacy. The people most likely to do it are either largely tech illiterate or skilled hackers with far too much time on their hands.
godot 4y ago
It really would benefit most people to learn to use (Windows) Snipping Tool or (Mac) cmd-shift-4 to crop an image that is currently displayed on their screen; that would create a new image altogether (cropped screenshot). It's truly even easier to use than whatever Gsuite or Office alternatives they would otherwise use, once you know of their existence. My significant other is outside of tech and wasn't aware of either of these. Once shown, there was no reason to go back to using anything else to crop images. No image editors involved!
- thrashh 4y ago
  Screenshotting an image will easily destroy resolution. It’s not a good way if you are making a document intended to be printed
  - albert_e 4y ago
    yes. saving a screenshot as JPG (lossy format) adds more loss - if you started with a lossy image in the first place then we are losing even more information by screenshotting it and saving it again in a lossy format. even when not intended for print, when making formal documents and presentations I look for the original images at highest resolution available.
    - alpaca128 4y ago
      Mac OS' preinstalled screenshot tool saves in PNG, same with Android screenshots. Not sure about Windows' Snipping Tool but it would surprise me if it was different there.
zellyn 4y ago
An increasing number of image editors are focusing on “non-destructive editing” too…
- alpaca128 4y ago
  That's true, but the information for that is usually stored in the image editor's own format, not in the exported image file.
  - TeMPOraL 4y ago
    Except when we're talking mobile apps. Samsung apps have a penchant for producing... enriched files in common formats. For example, "motion photo" feature I used few years ago would give you perfectly normal JPG file that also happened to store a short video. Nothing I know other than Samsung phones can read the video part directly, though there exists desktop software that can extract it and save as separate video file. More recently, I've noticed photo editor tools on Samsung phones allow you to undo previously made edits on an already saved file, including any destructive crops and transforms - meaning the original is being persisted somewhere. I haven't checked where, but I imagine it's again attached to the back of the JPG you thought you've cropped/redacted. Somewhat related: PlantUML. It's a tool for generating diagrams from plaintext descriptions. One of its most interesting, if not well-known, features is that it saves "editable PNGs" by default - that is, PNGs it produces have the plaintext diagram code attached to the image as metadata. Seems mostly harmless, but it could technically leak information you put in the diagram code but made not visible in the image.

tjoff 4y ago

Not foolproof, there have been instances when people have been cropping in an image-editor and failed to realize that the thumbnail hadn't been updated and leaked information.

a_shovel 4y ago
Okay, that one might catch me. I couldn't tell if an image had a thumbnail stored with it to begin with.
Hamuko 4y ago
If I need to ensure there's nothing on an image that wasn't supposed to be there, I just copy the visible pixels and paste it to a new document. No EXIF data, outdated thumbnails or anything.
- e28eta 4y ago
  I can actually imagine a tool that’d copy/paste the metadata along with the data, but I don’t know if any exist.
  - chihuahua 4y ago
    Using a screenshot tool should be safe. It will treat all pixels on the screen the same, so it doesn't know that some pixels have metadata beyond what's visible on the screen.
    - hef19898 4y ago
      Then print and scan the screen shot before faxing it to authorities.
      - toss1 4y ago
        And make sure that the scan is of low enough resolution that it fails to pickup the printer identification dot pattern in the printout... The fax should help with that, except that it'll reveal the location of your source fax. Using fax software/service needs its own security... maybe snail-mail... This is getting seriously nontrivial
        adolph 4y ago
        Don’t forget to pilfer newspapers from around the country and cut/glue letters from different fonts to compose the message and use homemade paper as the base layer.
        hef19898 4y ago
        Instead of home made, use the most prolific paper you can imagine!
        hef19898 4y ago
        Well, if we talk about goverbment whistleblower programs I assume using a fax from a random location while travelling would be good enough to not be identified by your employer (or whom ever you blow whistle on). If you do blow the whistel on the government, well, you better trust your journalist partner a lot. Or use a trustworthy lawyer as a go between. But hey, one could send the fax back and forth, cut of the fax numbers and physically mail it from a very busy train station! And have a someone put the letter into the letterbox for you, someone you pay out of view of any CCTV cameras!
        gregoryl 4y ago
        People who have information x, and were in location y (especially where y is not a common place for x holding people) will be a very limited set.
hilbert42 4y ago
"...failed to realize that the thumbnail hadn't been updated..." Right, I'd never use part of the original image. Best print it out and rescan it, preferably on different scanner. Being truly anonymous is enormously difficult, even the Bauer pattern/Bayer filter shape in one's image sensor will give one away. That alone requires sophisticated filtering to decouple it from a specific sensor/camera. And that's only the beginning, there are many other factors that contribute to the leaking one's identity.
- acuozzo 4y ago
  > Best print it out https://en.wikipedia.org/wiki/Machine_Identification_Code https://en.wikipedia.org/wiki/Machine_Identification_Code
  - jwestbury 4y ago
    Black and white from here on out, then.
    - hilbert42 4y ago
      Right. Good idea, see my 2nd comment.
  - hilbert42 4y ago
    I'm aware of that, hence my comment about the many other issues that have to be considered in decoupling information from hardware. 1. First, most whistleblowing comes from B&W documents so color isn't an issue. If it is the case then there are alternative solutions which I'll not persue here in any detail (the post would be very long). 2. Printing then rescanning can decouple the camera to some extent as physical distortions are introduced by (a) the geometry of the inkjet nozzles or laser subsystem, (b) more geometric distortion is added by changes in paper size as its fused/dried, (c) additional distortion is added by the optics of the rescanning system, same goes for any further printing and so on. Also, each stage alters the gamma and adds other non linearities to the transfer. 3. Reducing the scanning resolution will add additional distortions, blurring is to be encouraged but not to the point of illegibility. (Doing a low resolution copy on a FAX machine with time/date/headers/footers turned off could help.) 4. This may sufficiently decouple the camera but it won't decouple the copying/scanning/rescanning equipment. Best do this on machines that are located well away from the source so they're not easily traceable or associated with you or your work. 5. Copying documents across multiple different photocopiers will help as they all add optical and other geometric distortions and transfer—gamma-type—errors. Deliberately lightening and darkening the image at each stage will further increase distortions. The combined distortions will make it very difficult (but not impossible) to reverse engineer the path back to the source. Have you ever wondered why the quality of the printed type in copies of evidence, FOIs, official documents etc. often looks so daggy and blurred as to be almost illegible? 6. The idea is to add as much distortion and blurring in the chain of copies as is possible and yet still keep the final copy legible/identifiable. It's a fine balance. 7. That still does not guarantee anonymity. Sensitive documents are often 'doctored' so that each recipient receives a subtlety different copy, spacing between words may change so may the page layout, also small seemingly insignificant and barely obvious 'marks' on the page will differ between copies thus identifying each recipient. None of the camera techniques above will overcome this problem. 8. One technique is to retype the document so that it is almost identical in both looks and content but with lots of subtle changes in both layout and wording—but NOT to the extent of changing the document's meaning. Same goes for modifying images (a complex matter). As a last resort this could give you a degree of plausible deniability in cases where marked documents are issued. If you do this it would be very advisable to spirit away actual copies of the originals in a truly safe location—you may really need them one day (after you're accused of, say, forgery). I'd suggest you only go down this path if you are very competent and the stakes are very high. 9. None of what I've said should be taken lightly. No matter how hard you try to decouple yourself totally from the source (or from any involvement) it is nigh on impossible to hide from formidable and sophisticated forensics if applied relentlessly. 10. Moreover, whistleblowers, more often than not, end up being reveilled by fellow workers and usually without a job or decent reemployment prospects. Unfortunately, our culture hasn't embraced whistleblowers and whistleblowing as it should. It's a very risky business. Take the case of whistleblower Daniel Ellsberg and the Pentagon Papers; his effort wasn't rewarded as we ought to expect and he nearly ended up being locked up. Moreover, at one point Ellsberg wistfully noted that reaction by the American public to his efforts wasn't very favorable. When it comes to whistleblowing it seems not much has improved in the last five decades. _ Edit: FYI, there are many excellent videos on Daniel Ellsberg and whistleblowing on YouTube.
knodi123 4y ago
Referring to TechTV presenter Cat Schwartz, I presume? https://en.wikipedia.org/wiki/Catherine_Schwartz https://en.wikipedia.org/wiki/Catherine_Schwartz
8n4vidtmkvmk 4y ago
i just screenshot images. that way it'll lose any metadata. any parts outside of my screenshotted area can't be included... and i think the black rectangles are genuinely black in sharex...

kerblang 4y ago

I think I would do this by default because I'm so ignorant/incompetent with the fancier tools that I'd never think to look for a cropper. I'm the cretin that says, "Oh I can do this in MS Paint!" and even spends a 1/2 hour remembering how to do that much...

deleted 4y ago

[deleted]

bcrosby95 4y ago

Iirc some formats support cropping too. So even if you crop in an image editor, all the data may still be there.

SapporoChris 4y ago

I sometimes get smartphone photos of computer screens sent to me by friends. It makes me cringe every time, but now I'm thinking maybe they're onto something.

c0nsumer 4y ago
While I doubt they are meaning it as such, it's not far off from the technique of physically redacting a printout and then scanning that as duotone so there was never, ever a digital path between the original and the resulting digital copy.
LarryMullins 4y ago
I believe this is often done to avoid corporate surveillance on the computer that might record the screenshot and exfiltration.
- thrashh 4y ago
  I think it’s usually done because copying a file from a computer to a smartphone universally is still a pain in 2023 - Bluetooth file transfer… I don’t even know where to begin - AirDrop requires you to be in the Apple ecosystem. I think default settings also require you to be logged in the same Apple account on both devices too - Cloud storage services need you to install the app or login into the website on both your phone and the computer with the same account. Very few of my non-tech friends even have any cloud storage service outside what their phone uses Ngl, I take photos of my screens sometimes
  - albert_e 4y ago
    some other methods that work well in some cases: whatsappweb opened in a browser pushbullet google photos / Gmail to yourself
  - teo_zero 4y ago
    Attach the file to a draft email that you save without sending. You'll find it in the draft folder on both the computer and the phone.

burkaman 4y ago

> barely-tech-literate people I think this is a little unfair. I would not blame anyone for thinking that the part of the image they cropped is deleted. That's what the word means, that's what it looks like is happening, there's usually no warning that it's recoverable. When you delete text it is really gone from the document, even though you can undo to get it back. It's totally reasonable to expect images to work the same way.

a_shovel 4y ago
What I had in mind when I was writing that was a story I once read of a user who did all of her computer interactions through Word (i.e. all of her emails were empty with a Word document attachment containing the text, among a few other amusing anecdotes). But yeah, the characterization is a bit unfair from that perspective.
- alpaca128 4y ago
  I know a few people personally who mainly used Word (and increasingly also web browsers) when working on computers, and it's sometimes obvious they view everything a computer does through that lens. For some people only used to Windows even appstores are a foreign concept, a relative's first impulse when trying to install a phone app is to open the phone's web browser and do a Google search. Those are things many recent UI "improvements" haven't considered.
heavenlyblue 4y ago
Arguably even undo is probably now saved in the documents themselves.
wolrah 4y ago
OP isn't saying the person is barely tech literate because they didn't expect the image to be restorable, but that they're likely barely tech literate because they were using a word processor as an image editor. Abusing Microsoft Office applications to do things they're not designed to do has sort of a bathtub curve of likelihood versus tech literacy. The people most likely to do it are either largely tech illiterate or skilled hackers with far too much time on their hands.

godot 4y ago

It really would benefit most people to learn to use (Windows) Snipping Tool or (Mac) cmd-shift-4 to crop an image that is currently displayed on their screen; that would create a new image altogether (cropped screenshot). It's truly even easier to use than whatever Gsuite or Office alternatives they would otherwise use, once you know of their existence. My significant other is outside of tech and wasn't aware of either of these. Once shown, there was no reason to go back to using anything else to crop images. No image editors involved!

thrashh 4y ago
Screenshotting an image will easily destroy resolution. It’s not a good way if you are making a document intended to be printed
- albert_e 4y ago
  yes. saving a screenshot as JPG (lossy format) adds more loss - if you started with a lossy image in the first place then we are losing even more information by screenshotting it and saving it again in a lossy format. even when not intended for print, when making formal documents and presentations I look for the original images at highest resolution available.
  - alpaca128 4y ago
    Mac OS' preinstalled screenshot tool saves in PNG, same with Android screenshots. Not sure about Windows' Snipping Tool but it would surprise me if it was different there.

zellyn 4y ago

An increasing number of image editors are focusing on “non-destructive editing” too…

alpaca128 4y ago
That's true, but the information for that is usually stored in the image editor's own format, not in the exported image file.
- TeMPOraL 4y ago
  Except when we're talking mobile apps. Samsung apps have a penchant for producing... enriched files in common formats. For example, "motion photo" feature I used few years ago would give you perfectly normal JPG file that also happened to store a short video. Nothing I know other than Samsung phones can read the video part directly, though there exists desktop software that can extract it and save as separate video file. More recently, I've noticed photo editor tools on Samsung phones allow you to undo previously made edits on an already saved file, including any destructive crops and transforms - meaning the original is being persisted somewhere. I haven't checked where, but I imagine it's again attached to the back of the JPG you thought you've cropped/redacted. Somewhat related: PlantUML. It's a tool for generating diagrams from plaintext descriptions. One of its most interesting, if not well-known, features is that it saves "editable PNGs" by default - that is, PNGs it produces have the plaintext diagram code attached to the image as metadata. Seems mostly harmless, but it could technically leak information you put in the diagram code but made not visible in the image.