I had a big problem with several sellers on ebay using my photos,
especially a guy that runs a store called Hea.ven.ly Orchid (I put the
periods in so the jerk wouldnt get some free Google advertising). Some
were even editing off my watermark. Ebay was very quick to remove the
offending auctions and they set me up with a new ebay user name that
puts a "report it now" type button at the bottom of every auction page.
It automates the whole reporting process and its fast.

If you have a lot of pictures online check that sellers store, I sent
emails to about 5-10 other people that he was stealing images from. He
has a lot of complaints against him now.

Dustin