Wallpaper Less Saturated Than Source Image

I've noticed this before, but its been bothering me so I thought I would see if anyone else has noticed this...

When setting an image such as a JPEG or TIFF as the wallpaper in Windows 7, the actual wallpaper that is displayed on the desktop is noticeably LESS saturated than the original image.

Has anyone else noticed this?

I have attached a screen shot of what I am talking about. On the left is the actual image, on the right, is the exposed desktop. Notice that the green is much less saturated and has a yellow shift as compared to its source file, which is displayed with Windows Photo Viewer.

This is Windows 7 64-bit on a Sony VAIO VGN-NW240F. Integrated graphics.

Any thoughts?

Ok, did some testing and I've got it narrowed down to it being a compression issue. When windows reduces size of the original file to fit on the desktop, it must use a high compression algorithm, which causes a loss of saturation. I tested this by resizing the image myself in PS and setting that as the desktop wallpaper rather than letting Windows handle the resizing. Resulted in a wallpaper identical to the original file.

Just like when you save a jpeg with low quality settings, you get a less saturated image.