What I have found to work well is to load my images in an NSMutableArray using the addObject method with code as follows:
Code:
[myImageArray addObject:[UIImage imageWithContentsOfFile:[NSBundle mainBundle] pathForResource:@"image1" ofType:@"png"]];
Note that imageWithContentsOfFile does not cache the image in memory (which is generally better for most purposes to save memory).
I am using openGL now so I am actually adding Texture2Ds but the above code will work for regular images.