How to write or modify EXIF data for an existing image on the filesystem, without loading the image?

Question

I\'ve asked similar questions before, but have not received a definitive answer. Seems that there must be a way to simply add/modify metadata to an image without loading the

Answer 1

If you know how to modify the EXIF, you can modify the binary data directly from the file. Just replace in the image the binary portion with the new one. I don't know if objective-c permit this, but in ansi c should be simple. The complicate part is to identify the exact part to change.

Answer 2

You can use libexif - I've had success with compiling it for iOS before. With libexif, you can modify any image's EXIF metadata.