title: How to write exif metadata to an image (not the camera roll, just a UIImage or JPEG)
body: <p>I am aware of how to save metadata using ALAssets. But, I want to save an image, or upload it somewhere, with exif intact. I have exif data as an NSDictionary. But how can I inject it properly into a UIImage (or probably an NSData JPEG representation)?</p>