self.closeButton.frame = CGRectMake(itemImageX-10, itemImageY-10, 30, 30);
[self.closeButton setImage:[UIImage imageNamed:@"close"] forState:UIControlStateNormal];
self.closeButton.frame = CGRectMake(itemImageX-15, itemImageY-15, 35, 35);
[self.closeButton setImage:[UIImage imageNamed:@"close"] forState:UIControlStateNormal];
[self.closeButton setImageEdgeInsets:UIEdgeInsetsMake(5, 5, 5, 5)];
This will make the button bigger (and more easier to touch) but keep the image the same size. Feel free to play around with the numbers and let me know how you get on.
Cheers