mssfldt - 3:16 pm on Aug 3, 2010 (gmt 0)
What you discuss here is an old and really big problem. You can steal a picture on two ways: direct by copying or ... by hotlinking.
Stealing means that you can get the Google-Link and by this the traffic.
I have discovered this for a long time on different keys. E.g if you are searching fpr "cn tower" (sorry ;-) ), you will find a picture with a girl with big ... . There are hundreds of copies all over the world, and the picture ranks on many keys ( depending on the name the thief uses ). To find some of the copies you could use "similar images" or "tinyeye".
Because Google didn't know what the original picture is they change the target-URL in image-search by random. It changes every 2 - 3 days ( this is what I discovered. Perhaps someone here has found out something else ).
If you found out that somebody has stolen a picture by copying you could write hin directly or send a message to google.
The bigger problem is the "stolen link" by hotlinking. In this case you would not use the ( visible ) picture on your site but only a link to the source ( somewhere else ). By doing this you could also steal the link - also, if your page is not optimized to the key. The content of the page could be completely different.
Google does not use a "timestamp" ( when is the picture first indexed ) to declare which picture is the "original source".
And Google does not use the "size" of the picture to find the original ( the biggest picture should be the original ).
I have described the problem in Germany in my blog : especially "person-search-engines" like 123people or yasni uses these methods to generet ( steal ) traffic. They involve automatically the best Google-result-images ... and get by this often the link.
Big problem ...