I agree with Jaime. The problem with this one is the GIF's limited colors. The spiked histogram on Caitlins post means there's pixel information missing.
If you haven't done so, read about
SCANTIPS.COM- Image file format and which to use
Here's a little summary of it:
For Photographic images
- best quality for archived master: TIFF or PNG format
- smallest file size: JPG format
- maximum compatibility: TIFF or JPG format
- worst choice: GIF format
I'm sure a lot of people here will be able to solve your problem after your JPG post.