Forum changes color of uploaded images

[shijan]

It seems there is a bug in the Forum. It re-compress uploaded images and changes their color. So image start to look less saturated and also less sharp. Here is sRGB JPEG image uploaded directly to this forum:

rgb-cmy.jpg

Here is same sRGB JPEG image uploaded to other image hosting:

[bkh]

Looks like this does not happen if I upload the attachment using Apple Safari:

rgb-cmy-3.jpg

[Herbert123]

rgb-cmy.jpg

Test! Fine in Firefox Developer as well.

[shijan]

Interesting. I tested in Safari and there is no color shift.
I use Firefox 115.26.0 esr on macOS. I also enabled color management in Firefox by changing some gfx.color_management in about:config like described in this https://developer.mozilla.org/en-US/doc ... in_Firefox and this https://zidhuss.tech/posts/p3-firefox-mac/ articles. Maybe this somehow affect image during uploading? Maybe forum somehow reads my wide gamut display profile and incorrectly convert colors? I'll do some tests later with default Firefox settings...

[shijan]

Here is (partial) problem fix, just in case if someone will look for same problem. Problem was because i set Firefox about:config gfx.color_management.native_srgb to "false". It was done to apply color management to fonts and svg vector objects. But seems it also affect color of uploaded images. If set it to default "true", there is no problem with uploaded images, but fonts and vector objects in browser now look non color managed and too vivid. Guess i need to report this bug to Firefox team.