It seems the cat image is actually a video element and moving the mouse you are actually scrolling through the video. Interesting idea.

Would have been cool if the cats were looking at your mouse pointer similar to https://pointerpointer.com

Yup that is correct! I do like the idea of the cats looking at the mouse cursor. Would need to do some work figuring out how to interpolate just the pose part of the latent space.

It is not very clear. The idea is that I move the mouse over the image on the top left, and I get a different image for each point?

You can move your mouse anywhere on the screen and get different images for each point. Moving over the the cat vs. the fluid simulator doesn't make a difference, except that the points are mirrored over the Y-axis.