Setting image property of UIImageView causes major lag

Question

Let me tell you about the problem I am having and how I tried to solve it. I have a UIScrollView which loads subviews as one scrolls from left to right. Each subview has 10-

Answer 1

I think, the problem could be Images themselves. For example - I got in one of my projects 10 images 640x600 layered with alpha transparency on each other. When I try to push or pop viewcontroller from this viewcontroller.. it lags a lot.

when I leave only few images or use quite smaller images - no lag.

P.S. tested on sdk 4.2 ios5 iphone 4.