The standard for images on the web is sRGB, so images without an embedded profile should be assumed to be sRGB.
Reporter, do you have test cases for this issue?
(In reply to comment #1)
> Reporter, do you have test cases for this issue?
I've put an example as the URL. The left image has an embedded sRGB profile, whereas the right image is untagged. The untagged image should be displayed as sRGB - quoting from http://www.w3.org/TR/css3-color/ :
"the 'color-profile' property ...
This is the default behavior. All colors are presumed to be defined in the sRGB color space unless a more precise embedded profile is specified within content data. For images that do have a profile built into their data, that profile is used. For images that do not have a profile, the sRGB profile is used so that the colors in these images can be kept "in synch" with the colors specified in CSS and HTML."
and from http://www.w3.org/Graphics/Color/sRGB :
"We propose that all page elements defined in the style sheets be assumed to be in the sRGB color space unless embedded ICC profiles indicate otherwise."
(In reply to comment #2)
> For images that do not have a profile, the sRGB profile is used so that
> the colors in these images can be kept "in synch" with the colors specified in
> CSS and HTML."
Since WebKit does not color match the colors specified in CSS and HTML (at least not yet, though I personally find such behavior correct), this is a reason not to assume sRGB for untagged images right now.
See also: bug 5972.
Currently we have Firefox 3.0 that does color management. Isn't it a good time to return to this bug? Vast majority of images on the Web does not include color profile information and are indeed in sRGB. This means that WebKit users are always seeing incorrect colors except those that have their monitor color space very close to sRGB. Every MacBook user that starts Safari gets into the world of desaturated dull colors (webkit.org blogs contain many examples). People with high-end Adobe-RGB capable monitors see their images over-saturated. Many photographic sites are hardly usable (http://picasaweb.google.com/ being the prominent example)