You can convert your OpenGL image to a UIImage.

http://stackoverflow.com/questions/5062978/how-can-i-dump-opengl-renderbuffer-to-png-or-jpg-image

You can capture the current content of a UIView to an Image.

- (void) snapUIView
{
  UIGraphicsBeginImageContext(self.view.bounds.size);
  [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
  UIImage *myImage = UIGraphicsGetImageFromCurrentImageContext();
  UIGraphicsEndImageContext();
  UIImageWriteToSavedPhotosAlbum(myImage, nil, nil, nil);
}

How can we make an UIWebView transparent? If you want to display something under UIWebView, you should set the background color of an UIWebView to transparent. You can do it with two lines of code.

self.webView.opaque = NO;
self.webView.backgroundColor = [UIColor clearColor];

You should not use the following code because it not mentioned in Apple documents.

[webView setDrawsBackground:NO]