Overlaying UIImageview over UIImageview save

I'm trying to merge two UIImageViews. The first UIImageView (theimageView) is the background, and the second UIImageView (Birdie) is an image overlaying the first UIImageView. You can load the first UIImageView from a map or take a picture. After this you can drag, rotate and scale the second UIImageView over the first one. I want the output (saved image) to look the same as what I see on the screen.

I got that working, but I get borders and the quality and size are bad. I want the size to be the same as that of the image which is chosen, and the quality to be good. Also I get a crash if I save it a second time, right after the first time.

Here is my current code:

//save actual design in photo library
- (void)captureScreen {
    UIImage *myImage = [self addImage:theImageView ToImage:Birdie];
    [myImage retain];
    UIImageWriteToSavedPhotosAlbum(myImage, self, @selector(imageSavedToPhotosAlbum:didFinishSavingWithError:contextInfo:), self); 
}


- (UIImage*) addImage:(UIImage*)theimageView toImage:(UIImage*)Birdie{
   CGSize size = CGSizeMake(theimageView.size.height, theimageView.size.width);
   开发者_开发知识库UIGraphicsBeginImageContext(size);

   CGPoint pointImg1 = CGPointMake(0,0);
   [theimageView drawAtPoint:pointImg1 ];

   CGPoint pointImage2 = CGPointMake(0, 0);
   [Birdie drawAtPoint:pointImage2 ];

   UIImage* result = UIGraphicsGetImageFromCurrentImageContext();
   UIGraphicsEndImageContext();

   return result;
}

But I only get errors with this code! Thanks in advanced!

Take a look at Drawing a PNG Image Into a Graphics Context for Blending Mode Manipulation