Thanks to tineye I found a match after third try ...
this is my shot

And this is what I found, exactly the same picture signed by a Italian web page
Libero - Community Profilo di cat962
I went to that web page and fount my picture there too
http://www.sfondilandia.it/sfondi.asp?pag=...&order=nome
I looks like there a distributing my picture signed as theirs.
I know that what they did is illegal, but can anything be done about it? Any one had a similar situation and did something? Or should I just write to them and ask to remove the picture?