Radio buttons to slider?

1

How would I be able to make this “slide” between the images, rather than just switching them with buttons? It’s a landscape that changes with each click (img 2 alpha fades over image 1 on click), but it’s kinda clunky. I guess I’m asking if theres a way to build a slider that controls the alphas in AS, so it can go forward And backward on slide…

Here’s the file