4 ms·

Really? I've seen metadata scrubbed for privacy reasons, but never for size reduction. And realistically how much is saved in proportion to the image size?

by vdaniuk 13y ago

toomuchtodo 13y ago
Imgur and Craigslist specifically scrub EXIF metadata (EDIT thanks to /u/user24) for privacy.
- user24 13y ago
  - for privacy
  - toomuchtodo 13y ago
    Thank you. Edit made. Need moar coffee.
- porsupah 13y ago
  Which, sadly, also reduces the chances of finding who actually produced a given photograph. TinEye and Google Images can help, but, it can be surprisingly difficult to locate the actual origin of a given photo. (Let alone Tumblr and their infinite vortex of "reblog", which leads to more than a few dead ends)
walshemj 13y ago
Every little helps - Photoshop save for web can give you some quite usefull reductions I shaved 1 second of some key pages on kelley search just from optimizing a single image.
- catshirt 13y ago
  "Every little helps" but, does it? i mean it sounds like we're talking about taking a few bytes off a probably Xmb or XXmb image.
  - pjbrunet 13y ago
    Depends on the app. Multiply larger size x1000s of images, x1000s of visitors, x days. For offsite backups, 2x the storage cost. My general rule is, any image over 40k is too big for a web page, unless your website is about photography/high-resolution imagery. And I hate jaggies and compression artifacts as much as anybody ;-)
  - stan_rogers 13y ago
    One megabyte is huge for a web image. That's essentially a full-screen 4K/UHD version of a highly-detailed image with no detectable compression artifacts (where "detectable" means "image subtraction doesn't count; zoom in tight and use your eyes") when run through a good optimizing utility. That's good enough for a better-than-acceptable (not optimal, but from a pace or two away most people wouldn't notice) tabloid/A3 print without uprezzing. And there is enough data to support substantial uprezzing before the image goes wonky for those inclined to do so. Now, yer average pro doesn't tend to indulge in the pixel-peeping game (except in private, with the lights down low and the door locked, and always washes his/her hands afterwards), and tends to be reluctant to give away images that can still sell - or at least would prefer it if people kept their own Photoshop/Gimp chocolate out of their personal peanut butter. Even when the images are offered as freebies, there is no reason to force a viewer to download more than they need to make decisions; the hi-rez image will sit behind a link, to be opened at the viewer's discretion. The back button hurts everybody.
    - catshirt 13y ago
      who said anything about reducing the filesize by a megabyte? i assumed the EXIF data was maybe a few kb. not sure why i'm being downvoted. i get it, "every little bit" adds up. but here in the real world removing the EXIF data to save bandwidth is a micro optimization 99% of the time.
      - TuringTest 13y ago
        The grandparent meant that you wouldn't be removing a few kbs from "a probably Xmb or XXmb image", since web images aren't that large. You're right that it doesn't make sense to downvote you for that; it was an interesting question.
cbr 13y ago
This is one of the optimizations mod_pagespeed makes by default: https://developers.google.com/speed/pagespeed/module/filter-image-optimize#strip_image_meta_data https://developers.google.com/speed/pagespeed/module/filter-... There's not usually much EXIF text but it isn't gzipped so it's more expensive than need be. This is the kind of tweak that's not really worth doing on its own but when you're already optimizing the image you might as well do this too.
- miahi 13y ago
  It's not about the text, but usually the EXIF also contains a thumbnail (for faster display on the camera) that can take tens of KB.
  - coldtea 13y ago
    And some images also contain a color profile as metadata -- which can be quite large.
jcampbell1 13y ago
It can make a huge difference. `convert from_camera.jpg -resize 200x200 resized.jpg` `exiftool -all= resized.jpg -o resized-exif-stripped.jpg` from_camera - 2.4M resized.jpg - 33K resized-exif-stripped.jpg - 16K In this simple example, the EXIF data double the file size of a 200x200px thumbnail.
- jordibunster 13y ago
  Is that number from ls(1) or from du(1)?
  - jcampbell1 13y ago
    ls -h

Really? I've seen metadata scrubbed for privacy reasons, but never for size reduction. And realistically how much is saved in proportion to the image size?

by vdaniuk 13y ago

Really? I've seen metadata scrubbed for privacy reasons, but never for size reduction. And realistically how much is saved in proportion to the image size?

toomuchtodo 13y ago

Imgur and Craigslist specifically scrub EXIF metadata (EDIT thanks to /u/user24) for privacy.

user24 13y ago
- for privacy
- toomuchtodo 13y ago
  Thank you. Edit made. Need moar coffee.
porsupah 13y ago
Which, sadly, also reduces the chances of finding who actually produced a given photograph. TinEye and Google Images can help, but, it can be surprisingly difficult to locate the actual origin of a given photo. (Let alone Tumblr and their infinite vortex of "reblog", which leads to more than a few dead ends)

walshemj 13y ago

Every little helps - Photoshop save for web can give you some quite usefull reductions I shaved 1 second of some key pages on kelley search just from optimizing a single image.

catshirt 13y ago
"Every little helps" but, does it? i mean it sounds like we're talking about taking a few bytes off a probably Xmb or XXmb image.
- pjbrunet 13y ago
  Depends on the app. Multiply larger size x1000s of images, x1000s of visitors, x days. For offsite backups, 2x the storage cost. My general rule is, any image over 40k is too big for a web page, unless your website is about photography/high-resolution imagery. And I hate jaggies and compression artifacts as much as anybody ;-)
- stan_rogers 13y ago
  One megabyte is huge for a web image. That's essentially a full-screen 4K/UHD version of a highly-detailed image with no detectable compression artifacts (where "detectable" means "image subtraction doesn't count; zoom in tight and use your eyes") when run through a good optimizing utility. That's good enough for a better-than-acceptable (not optimal, but from a pace or two away most people wouldn't notice) tabloid/A3 print without uprezzing. And there is enough data to support substantial uprezzing before the image goes wonky for those inclined to do so. Now, yer average pro doesn't tend to indulge in the pixel-peeping game (except in private, with the lights down low and the door locked, and always washes his/her hands afterwards), and tends to be reluctant to give away images that can still sell - or at least would prefer it if people kept their own Photoshop/Gimp chocolate out of their personal peanut butter. Even when the images are offered as freebies, there is no reason to force a viewer to download more than they need to make decisions; the hi-rez image will sit behind a link, to be opened at the viewer's discretion. The back button hurts everybody.
  - catshirt 13y ago
    who said anything about reducing the filesize by a megabyte? i assumed the EXIF data was maybe a few kb. not sure why i'm being downvoted. i get it, "every little bit" adds up. but here in the real world removing the EXIF data to save bandwidth is a micro optimization 99% of the time.
    - TuringTest 13y ago
      The grandparent meant that you wouldn't be removing a few kbs from "a probably Xmb or XXmb image", since web images aren't that large. You're right that it doesn't make sense to downvote you for that; it was an interesting question.

cbr 13y ago

This is one of the optimizations mod_pagespeed makes by default: https://developers.google.com/speed/pagespeed/module/filter-image-optimize#strip_image_meta_data https://developers.google.com/speed/pagespeed/module/filter-... There's not usually much EXIF text but it isn't gzipped so it's more expensive than need be. This is the kind of tweak that's not really worth doing on its own but when you're already optimizing the image you might as well do this too.

miahi 13y ago
It's not about the text, but usually the EXIF also contains a thumbnail (for faster display on the camera) that can take tens of KB.
- coldtea 13y ago
  And some images also contain a color profile as metadata -- which can be quite large.

jcampbell1 13y ago

It can make a huge difference. `convert from_camera.jpg -resize 200x200 resized.jpg` `exiftool -all= resized.jpg -o resized-exif-stripped.jpg` from_camera - 2.4M resized.jpg - 33K resized-exif-stripped.jpg - 16K In this simple example, the EXIF data double the file size of a 200x200px thumbnail.

jordibunster 13y ago
Is that number from ls(1) or from du(1)?
- jcampbell1 13y ago
  ls -h