It's not just you. Most (independents) whom have reviewed IE7 have, as you, noticed/stated that images are clearer with Firefox.
Quote:
|
As far as image handling goes, Microsoft has included smart dithering, and they claim to have improved image display quality, but PNGs still look a little crunchy. Photographs especially are still much clearer in Firefox and Opera at this point. Viewing photos in IE7 curiously makes them appear slightly desaturated and washed out.
|
~Webmonkey
How Does IE7 Stack Up?