CGRect screenRect = [[UIScreen mainScreen] bounds];
CGRect rect = imageView.frame;
rect.size.height = screenRect.size.height;
rect.size.width = screenRect.size.width;
imageView.frame = screenRect;
[scrollView addSubview:imageView];

[imageView setAutoresizesSubviews:YES];
[imageView setAutoresizingMask:UIViewAutoresizingFlexibleWidth];

[imageView setAutoresizesSubviews:YES];
[imageView setAutoresizingMask:UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight];