here's what i think to be an easier way to resize and image.
Code:
UIGraphicsBeginImageContext( newSize );// a CGSize that has the size you want
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
//image is the original UIImage
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
newImage is your newly created image with the size you want