Did a little tinkering. If I convert files to sRGB colorspace, there is no problem (other than the slight changes that the conversion itself causes). The colors in the images are no longer grossly off. This is true for icons and for the screensaver. The odd thing is that on my older iMac (same OS), the icons and the screensaver are clearly colorspace aware because they are displayed properly withour requiring a colorspace conversion on the files. Any thoughts?