Flash movie lags badly if I add 1 more picture

I have flash gallery which doesn’t load pictures dynamically, just has them placed on stage. I have 12 pictures. It lags badly like this, but if I delete ANY of the 12 the movie plays smooth as silk. Is there anyone who has experienced this problem and can help me figure out how to solve it?

Any transparency?

The images not currently displayed have alpha of 0. I fixed the horrible stuttering at the start by making them _display false. Now it just hitches a bit when it first loads as all the images fade in. I can’t seem to fix it.