AI images Filename extension

Okay, thank you so much for the information!

@hmartinov @Rachael4 there is already metadata embedded in AI generated assets from Content Credentials:

https://helpx.adobe.com/firefly/get-set-up/learn-the-basics/content-credentials-overview.html

Upload your image to https://contentcredentials.org/verify and see the embedded data.

Or, if not a file extension, something in the image metadata that can indicate it was created by AI would be helpful.  In the gallery, when I click on an image that somebody else has generated to look at it closer, there's a little icon on the top right corner that when I hover over it, it says "Content Credentials" and that it is generated from AI, but when I've used Firefly myself and downloaded images from it, I can't find these Content Credentials anywhere.