Problem with packager for iphone and images

Hi, first Sorry for my english

I’m programming an application for iphone in flash cs5, the application is a gallery.
In the application i load 20 jpgs more or less and i put the jpgs in a vertical list and i do scroll, but when pass the aplicattion to the iphone, the aplication moves slow.
To load the images i use a loader, and i put all thumbs in a movieclip, to do the scroll i use:

Whats the problem?