Watermark hook

Hi!

Thank you for the great plugin — I really appreciate it!

I’d like to add watermarks to the converted WebP images. Could you help me with the best way to do this using your code? I’d prefer not to modify the plugin directly to avoid breaking anything.

Ideally, I’m looking for a safe method, such as a hook I can attach to — something that gives me access to the image just before it gets converted to WebP.

My goal is to upload clean (non-watermarked) images to the server and apply watermarks only during the WebP conversion. That way, I’ll always have the original, unwatermarked images stored on the server.

Thanks in advance!