XHTML Transitional Validator problem

Hello. I'm not sure what is the problem but please check this link
http://validator.w3.org/check?uri=http%3A%2F%2Fwww.clevershoppers.com%2Fcata
logv13%2F
 
I have strange error saying  that there is no alt tag.... i tried to remove
this link or add link before and validator moved this error to new links....
so only first link contain this error. 
 
Is it validor bug or i have soem problem with my code?
 
Sincerely, Dmitry