Forward & Reversing animation per frame

Does anyone have any documentation or tutorials on how to create nice forward & reverse slide transitions with the tween or tweener class? I’m trying to create a slideshow with 15 images on frame #'s 5-20. I have “Next” & “Back” buttons to navigate through each frame.

The problem: When a user clicks on the “Next” button a nice tweener transition of the old image out and the new image in happens. So, when the “Back” button is clicked, it’s chops to the original animate in animation for each frame. How can i animate the current slides image back out and the previous slides image back in?

Does that make sense? I’ve gone cross-eyed… ( .)(. )