HI,
Just to check.
How many different apps did you try and how many different Mac User Accounts ?
I see you mentioned two apps originally.
iChat ?
iMovie ?
Quicktime Player ?
Any of the snap shot options ?
System Preferences > Accounts > your Account and change the Pic ?
The Buddy Pic in iChat.
The Pic on Your Card (the My Card) in the Address Book ?
It is most likely the Store or an Apple Authorised Service Provider will be the answer if the SMC or PRAM resets have not worked - but they are not infallible.
8:51 PM Tuesday; May 28, 2013
iMac 2.5Ghz 5i 2011 (Mountain Lion 10.8.3)
G4/1GhzDual MDD (Leopard 10.5.8)
MacBookPro 2Gb (Snow Leopard 10.6.8)
Mac OS X (10.6.8),
Couple of iPhones and an iPad
"Limit the Logs to the Bits above Binary Images." No, Seriously