dvmc

Facebook actually keeps the photos in JPEG. Following your pointer, Facebook also converts them to WebP. The WebP version of public images can be accessed by just changing the file extension in the URL. You can check the ICC profile with ImageMagick's convert binary: convert -verbose photo.jpg Facebook automatically attaches its ICC profile to the photo (or overwrites the old one), which makes it seem darker. I've yet to find how to prevent FB from doing that.

Thanks! Nice to know. I actually use that program quite often, but never noticed that it solves the problem. Regarding the JPEG problem: It seems that Facebook applies another ICC colour profile, and thus the image seems darker. Probably the Windows Image Viewer just ignores the profile - that's why it's displayed correctly after downloading the converted image. Some research led me to the conclusion to add an ICC sRGB colour profile, but it doesn't work. It's simply overwritten by Facebook. Any ideas?

Hello! I have some trouble with the brightness with images created with Paint.NET: When I save an image as PNG, Firefox displays it darker than it should be, but Chrome and Windows Image Viewer (XP) display it just like Paint.NET When I save an image as JPG, Firefox, Chrome and Windows Image Viewer show them just like Paint.NET. But when I upload them to Facebook, where the image gets converted, the resulting image is darker than it should be - on Firefox and Chrome, but not on the Windows Image Viewer. A quick research led me to the conclusion that it has something to do with the colour profiles, but I couldn't figure out how to solve this problem. TL;DR: I want to have images created with Paint.NET to show up the same in major browsers, including conversion by Facebook (quality doesn't matter, but brightness does). Thanks in advance!