HELP! My Mobile has a virus!

Hi,

 

when I take pictures with my Nokia N97 Mini they somehow change over the next few minutes/hours/days into pictures of women's legs! This may be someone's idea of a joke ap or a virus, I'm not sure, but I've lost some very precious photographs. Does anyone know how to get rid of this?

 

I'm running a Trend Micro Internet Security package already, although it cannot detect any issues.

 

Thanks...