I am having the same problem. Froogle is crawling many of my add to card and seal of approval images instead of the actual products itself. Not all but many.
I have also found that several of my customers saw images on froogle and when they click on it were sent to another image of a different product all together.
This is happening because froogle crawls are too far and too few in between that they are displaying old images or discontinued items or out of stocks and when someone click on your link it can not locate the item because is no longer there.
It a good system but still has its kinks to work out.