I hope you can understand my question. As you click on each
button in this animation (link below), a picture is shown like a
gallery according to which button the user clicks on. When I click
on a button to go to a picture, it follows through nicely when
going forward, but if I want to go back the gallery doesn't reverse
through the pictures, it just goes back to the beginning in frame 1
and then finds the picture.
You are thinking in the wrong terms, this is done easier
without using the timeline.
I've written a very simple example, not very good code (in a
hurry) - but it works and illustrates an approach.
Open Flash, create a new document and paste in this code: