I agree with Dani, I have never heard of this being done with Google Analytics. In fact, I think it is very hard to determine the accuracy of images. I would be more inclined to think that it is easier to count the click through rate (CTR) on banners and links, but not necessarily on images. I may be wrong, but I think you are better off doing it that way. There are many trackers out there, I think it is a matter of trial and error. Testing a few of them and deciding which one works best for you.
articlewriter1 23 Junior Poster in Training
Acroagogue commented: Good post +0
articlewriter1 23 Junior Poster in Training