Forum:Strange image compression?

Hi, I've recently noticed a number of subtle changes concerning images on wikia. One of these is an occurrence where an image is uploaded to a wiki, in this case the Full Metal Panic! wiki and after being used in an article it appears pixelated and with a small degree of noise. {C Compare this with this one. Here, the first image appears fine but the second has the above changes after being used on the main page slider. Is it possible to prevent this happening? Any help would be appreciated. Kozakuu 14:42, March 24, 2012 (UTC)


 * I don't see a difference, try purging by going here to force the page to reload, then purge it. Thanks, Iggyvolz 14:51, March 24, 2012 (UTC)


 * I've purged page data and my browsers cache. The images used in articles are noticeably clearer but are still not as clear as those not used in articles. Kozakuu 15:25, March 24, 2012 (UTC)


 * Yes, there's a difference. It appears that Wikia has recompressed your image. The first one's size is 200K. The second one's only 70K.


 * I never experienced this myself, but I also never uploaded 200K images. 200K is too large. Not just for Wikia. It's too large for anything but a dedicated image site. Try to get the file size as far below 100K as possible before you upload the image! Use smush.it if you don't have a decent image editor. --


 * The size of the image isn't really the problem in this case, and compressing the jpg further would cause more artifacts, not less. The problem is caused by Wikia's servers compressing the image files when they are used on a page, and JPG is a file type that has lossy compression. My advice is that you should convert the image into a PNG file. PNGs are less likely to lose quality during compression. --Gardimuer { ʈalk } 22:57, March 24, 2012 (UTC)