I use a MAC to develop websites on which is set to Million's of Colours so this problem only came to my attention when tested on our PC
The pages have a websafe background of #333333. The problem images are the lower right background images on each page. It's not too noticable when there's text infront eg. on the Main page, but if you look at an empty page eg. contact, it's very apparent.
The photoshop files blend nicely and no matter what settings i save these images at JPG/GIF, with all variants, dithered, non-dithered, system, perceptual etc. etc. i can't get rid of the 'hard' fade
Can some of you guys change your monitor colour depths and tell me if there's a real problem or i'm just being paranoid. It tends to work fine on some and not on others. Less than ideal, to make it worse i think it also depends on gamma settings as well.
My results are........
256 Colours - OK
1000's Colours - Image fade shows up
Million's Colours - OK
256 Colours - Passable, Image fade shows up a little
High Colour (16bit) - Image fade shows up
True Colour (24bit) - Passable, Image fade shows up a little
Having developed many websites over the past few years, this is the first time i've had this problem.
I see the problem and I in my experience it only happens when you save your image as a .JPG, it seems you have saved it as a .GIF so I have no idea why it happens. Have you tried using the Save For Web... feature?
i think what you're seeing is some leftover artifacts from switching the color space settings. i did get it to band when swithching between high and true color settings, but hitting reload cleared the problem. i don't think you have anything to worry about. as it looked good in both settings when i hit reload.