elaborating a bit :
- the issue occurs in IE, Safari and Firefox
- I have Flash 10
- removing EXIF and IPTC metadata from the photos does not help.

I'm running Windows 7 x64 and the colors look just as vibrant in normal mode as they do in fullscreen mode on my PC (I've now viewed your page in IE8, Firefox and Safari).

I don't think this is the problem in your case but it might be worth a try as it's another color-related FAQ:
http://simpleviewer.net/simpleviewer/su … trouble_13

I can also confirm that it looks fine in Windows 7 64bit. After you made the change did you clear your browser's cache?

Is you monitor at an angle so when the image changes positions between normal and fullscreen it looks different? Have you tried removing flash and reinstalling? Adobe also as a beta version of a naive 64bit flash player that you can download. You could also try something like ccleaner to give your browser and flash's cache a good cleaning, as you may have a older version of SimpleViewer cached that does not use the color corrected swf.