Yea Jerboa is fucked for many users when it comes to zip’s avif images. Main reason I stopped using the app. They display fine on Voyager, for example:

I’m personally not a fan of it either, but it’s an easier load and less storage used on the server. I doubt anything will be done from Jerboa’s side to accommodate this since they’ve stopped development for the app, but oh well

For what it’s worth, the screenshots are the ones from the itch.io page