How to keep pics at same res.?

Hi !!

I am making a movie and my laptop has resolution of 1280*800 or something like that and I put some pictures in the movie. Now, when I run the flash movie in full screen pictures become a bit bigger and loose quality… how can I make it so that the pictures stay at their original size (the size of I assign in Flash MX 2004 Pro) regardless of how I resize the movie ?

Thanks