Button hover and unhover to set images

I would like to set button hover to switch images in UI widget, the process will be as follows:

When Beckett is selected, image 0 will be set, hovering Penfold is changing image 0 to image 1 and when unhovering Penfold image will be set back to image 0.

When Penfold is seleted, image 1 will be set, hovering Beckett is changing image 1 to image 0 and when unhovering Beckett, image will set back to image 1.

I have created the code but it looks that this code does not working.

Anyone know has any idea? Thank you.