It sounds very suspicious,
What security suite do you have installed,
Have you downloaded any new software,
What photo editor/ viewer do you use,
A few very good and free scanners are here you can try,
FYI, free scanners need to be manually updated before running full scans,
And only use one at a time and try not to use your computer during the scans,
http://www.malwarebytes.org/products/malwarebytes\_free
http://www.superantispyware.com/?tag=SUPERANTISPYWARE
http://www.microsoft.com/security/scanner/en-us/default.aspx
The last one usually takes four hours to complete.
Lets run these and I have one more thing to try after.