Save entire and visible image in UIScrollView when zoomed

Question

Hi friends i have small assignment on to zoom in and out a image .. for that i have used UIscrollView and UIImageView , zooming in and out works fine for me however i need save entire and visible (visible area on screen) image in UIScrollView when zoomed in or out If any body has any idea how i can please share with me . i stucked with same from last 2 days. I tried with follwing code not worked for me .

    UIGraphicsBeginImageContext(scrollView.contentSize); 

UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();

CGSize changedSize = viewImage.size;

UIGraphicsEndImageContext();

UIImageWriteToSavedPhotosAlbum(viewImage, nil, nil, nil);