Audio Keyframes Question/Help - Is it possible to sync 2 interchanging images to audio keyframes?

Hello,

I'm trying to make a video. The idea is that I've got a cartoon hand puppet speaking. I've got 2 images, one of the puppet's mouth closed, and the other open - is there a way to make it so that the 2 images change between each other in sync with the audio keyframes? Or is it only for scale, rotation etc. ?

Jw if there's a quicker or efficient way for this stage of the process because it's a little bit of a faff syncing the opening and closing of the images to 9 minutes of talking audio.

Thank you