aristotle - 8:50 pm on Jan 21, 2013 (gmt 0)
Beibg near the top isn't as important for image search as it is for regular search, because people tend to scroll down through the page and can scan through a lot of images in a short time. In order to attract clicks, you need something that's different and stands out from the crowd.
Unfortunately, searchers usually just want to see the image and don't click through to visit your site. Another problem is that image theft is even more common than content theft, so if you image stands out from the crowd, someone will likely steal it, and for whatever reason Google usually has no idea who had it first.