How to crop an image?

How would you crop an image using CGrectMake? I'm having a lot of trouble. Thanks!

Here is the code im using...

Code:

UIImage *spriteImage = [UIImage imageNamed:@"spritesheet.png"];
	
sprite.image = spriteImage;	
	
sprite.frame = CGRectMake(110.0, 180.0, 100.0, 100.0);