Last modified: 2010-08-18 13:32:50 UTC
Hi, (apologies if this is a dupe, the search function sucks) When the wiki resizes an image, it seems to do so using a wacky color space. For example, see this original image: http://upload.wikimedia.org/wikipedia/en/e/e0/Penny_Harvest_Field_2007.jpg and then compare to this automatically generated one: http://en.wikipedia.org/wiki/Image:Penny_Harvest_Field_2007.jpg Notice the red window in the background - it's clearly changed to a much lighter shade. This is not a browser issue, as you can download the image and verify in other programs. Disclaimer: I'm testing on a Mac, using Safari. It's possible on some browsers the color space may be ignored for both images, thus hiding the bug.
Firefox 3.0.3 ignores the color space, and appears to show both images about the same. I can confirm that Safari shows the original image a little darker (eg with color correction), though honestly most lay people will never notice the difference. ;) Not sure offhand what would be required to pass the color space information through to the thumbnail.
For another example, compare original: http://upload.wikimedia.org/wikipedia/en/b/b8/Highsmithvenicecanals.jpg vs. thumbnail: http://en.wikipedia.org/wiki/Image:Highsmithvenicecanals.jpg On my monitor at least, the difference is very noticeable. The thumbnail looks very pale and washed out.
The example image given above was moved to Commons: original: http://upload.wikimedia.org/wikipedia/commons/b/b8/Highsmithvenicecanals.jpg preview: http://commons.wikimedia.org/wiki/File:Highsmithvenicecanals.jpg That said, the original image looks terrible with Firefox 3.5.6.
Perhaps the best solution might be to force-convert all images to sRGB upon upload? When using a Mac at least, it's very common for photos to be generated using something like Adobe RGB, and the uploader might not even realise that most non-Safari browsers won't show these properly.
color profiles should now be preserved by the thumb system (Bug 19960). That doesn't negate that some browsers don't interpret them at all of course.
*** This bug has been marked as a duplicate of bug 19960 ***
