I just spent a day trying to fix a problem I never understood, thinking a massive performance slowdown was due to the excellent PSTCollectionView class. Nope.
In the end it was this line of code that brought my UI to a halt:
UIEdgeInsets stretchInsets = UIEdgeInsetsMake(23.9, 97.0, 9.9, 9.9); // BAD!!! Must be int values! normalImage = [normalImage resizableImageWithCapInsets: stretchInsets];
A word to the wise: When using UIEdgeInsets to create a resizable UIImage, BE SURE to use integer values and not floats! Otherwise some crazy interpolation takes place and the whole UI just dies.
I just saved you time. Just remember this.