Write image metadata to JPG/PNG file in iOS

Question

Is there any way to write a UIImage to a JPG/PNG file and then append metadata to it? I know you can use:

writeImageDataToSavedPhotosAlbum:metadata:completionBlock

to do this in the Saved Photos, but how do you do the same thing directly to a file? I can't seem to find any way to do this. I know that UIImagePNGRepresentation() and UIImageJPGRepresentation() will give you NSData that you can use to write the file, but there's no way to append/replace the metadata in the file.

Any ideas?

Answer 1

Looks like a duplicate.

To add metadata to a UIImage you can use the ImageIO framework You can create a CGImageDestination object from a UIImage, add metadata to it using CGImageDestinationSetProperties and then get the raw data (which includes the compressed image and the metadata) from it.