4 ms·

The files in the before/after preview slider are exactly the same file size when they're supposed to be showing how their compressed image looks as good as the

The files in the before/after preview slider are exactly the same file size when they're supposed to be showing how their compressed image looks as good as the original. They're also not the same files you get when you click the download button.

drorgill 14y ago
Those are just preview files used for fast page load, but they are based on resized versions of the original and the JPEGmini version. You are welcome to download the original and JPEGmini full resolution files, and compare them at "Actual Size" (100% zoom).
- nwh 14y ago
  If you get two large images and resize them down to a small preview, they'll look the same. It's really complete bullshit showing those as "examples".
- lwat 14y ago
  I downloaded the pic of the dog, opened the 'Original' in Paint.net, re-saved it at the same filesize as the JPEGmini version and it's indistinguishable from the other two versions. JPEGmini doesn't seem to do anything that I can't already do in any image editor. Looks like snake oil to me.
  - drorgill 14y ago
    Note my previous reply on this issue: JPEGmini adaptively encodes each JPEG file to the minimum file size possible without affecting its original quality (the output size is of course different for each input file). You can take a specific file and tune a regular JPEG encoder to reach the same size as JPEGmini did on that specific file. And you can also manually tune the quality for each image using a regular JPEG encoder by viewing the photo before and after compression. But there is no other technology that can do this automatically (and adaptively) for millions of photos.
    - mistercow 14y ago
      >JPEGmini adaptively encodes each JPEG file to the minimum file size possible without affecting its original quality That is indeed what the FAQ says, but that being the case, the tool does not actually work very well, and the presentation is incredibly dishonest. The fact is that the JPEGmini versions of these images do lose noticeable quality, but Beamr is hiding this by giving a demo where the images are shown at 25% scale. Take the dog image, for example. Using the slider, you'd think that JPEGmini nailed it; no visible artifacts whatsoever. But let's look at a section of the image at 100% scale, and see if this tool is really that impressive: http://imgur.com/z12mHnd http://imgur.com/z12mHnd ...holy block artifacts Batman!
      - crynix 14y ago
        I hope you're aware imgur compresses images that you upload to it regardless of whether they were already compressed.
        mistercow 14y ago
        Maybe they do that for lossy images, but I just compared what's on imgur to the original on my computer, and it is pixel-for-pixel identical. They did shave about 7KB off of it though, so maybe they push PNGs through pngout or similar. I mean, as far as I know, there aren't even any practically useful algorithms out there for doing lossy compression on PNGs (although there should be).
        nitrogen 14y ago
        Fireworks, pngquant, and png-nq have quantization algorithms that will dither a 32-bit PNG with alpha down to 8-bit palletized PNGs with alpha. The palette selection algorithms the free tools use (I haven't used Fireworks) sometimes drop important colors used in only a small section of an image, resulting in a blue power LED losing its blue color.
        mistercow 14y ago
- deleted 14y ago
  [deleted]

drorgill 14y ago

Those are just preview files used for fast page load, but they are based on resized versions of the original and the JPEGmini version. You are welcome to download the original and JPEGmini full resolution files, and compare them at "Actual Size" (100% zoom).

nwh 14y ago
If you get two large images and resize them down to a small preview, they'll look the same. It's really complete bullshit showing those as "examples".
lwat 14y ago
I downloaded the pic of the dog, opened the 'Original' in Paint.net, re-saved it at the same filesize as the JPEGmini version and it's indistinguishable from the other two versions. JPEGmini doesn't seem to do anything that I can't already do in any image editor. Looks like snake oil to me.
- drorgill 14y ago
  Note my previous reply on this issue: JPEGmini adaptively encodes each JPEG file to the minimum file size possible without affecting its original quality (the output size is of course different for each input file). You can take a specific file and tune a regular JPEG encoder to reach the same size as JPEGmini did on that specific file. And you can also manually tune the quality for each image using a regular JPEG encoder by viewing the photo before and after compression. But there is no other technology that can do this automatically (and adaptively) for millions of photos.
  - mistercow 14y ago
    >JPEGmini adaptively encodes each JPEG file to the minimum file size possible without affecting its original quality That is indeed what the FAQ says, but that being the case, the tool does not actually work very well, and the presentation is incredibly dishonest. The fact is that the JPEGmini versions of these images do lose noticeable quality, but Beamr is hiding this by giving a demo where the images are shown at 25% scale. Take the dog image, for example. Using the slider, you'd think that JPEGmini nailed it; no visible artifacts whatsoever. But let's look at a section of the image at 100% scale, and see if this tool is really that impressive: http://imgur.com/z12mHnd http://imgur.com/z12mHnd ...holy block artifacts Batman!
    - crynix 14y ago
      I hope you're aware imgur compresses images that you upload to it regardless of whether they were already compressed.
      - mistercow 14y ago
        Maybe they do that for lossy images, but I just compared what's on imgur to the original on my computer, and it is pixel-for-pixel identical. They did shave about 7KB off of it though, so maybe they push PNGs through pngout or similar. I mean, as far as I know, there aren't even any practically useful algorithms out there for doing lossy compression on PNGs (although there should be).
        nitrogen 14y ago
        Fireworks, pngquant, and png-nq have quantization algorithms that will dither a 32-bit PNG with alpha down to 8-bit palletized PNGs with alpha. The palette selection algorithms the free tools use (I haven't used Fireworks) sometimes drop important colors used in only a small section of an image, resulting in a blue power LED losing its blue color.
        mistercow 14y ago
deleted 14y ago
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