Merge two UIImage to make single UIImage.

- (UIImage*)mergeImage:(UIImage*)first withImage:(UIImage*)second

{

 // get size of the first image

 CGImageRef firstImageRef = first.CGImage;

 CGFloat firstWidth = CGImageGetWidth(firstImageRef);

 CGFloat firstHeight = CGImageGetHeight(firstImageRef);

 // get size of the second image

 CGImageRef secondImageRef = second.CGImage;

 CGFloat secondWidth = CGImageGetWidth(secondImageRef);

 CGFloat secondHeight = CGImageGetHeight(secondImageRef);

 // build merged size

 CGSize mergedSize = CGSizeMake(MAX(firstWidth, secondWidth), MAX(firstHeight, secondHeight));

 // capture image context ref

 UIGraphicsBeginImageContext(mergedSize);

 //Draw images onto the context

 [first drawInRect:CGRectMake(0, 0, firstWidth, firstHeight)];

 [second drawInRect:CGRectMake(0, 0, secondWidth, secondHeight)]; 

 // assign context to new UIImage

 UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

 // end context

 UIGraphicsEndImageContext();

 return newImage;

}