Gallery w/ thumbs

right now i’m doing a image gallery that’s basically like this (except the thumbs are above):

however i’m not following that because there’s no transitions… i want it to be simple; click and there’s the picture. you know what i mean?

i have the thumbs on a different layer than the MC that hold the actual pictures. i’m having problems linking the thumbs and images together. i don’t know how!

if my thumb is a button called thumb_0 and the main image is called image_0 how do you link the images together? also the MC is called viewer.