@Taufo,
Here is a suggestion:
You'll need to have thumbnail images (e.g. use buttons with image background). Place them in a screen arrangement. Make the arrangement visible
Now In another screen arrangement, drop in image component and under it a button image to to "Go Back". Make this arrangement hidden.
Once a thumbnail is clicked, get its associated large image name (e.g. from a list or some type of naming convention), and then set it to the image in the 2nd arrangement. Now make the 1st arrangement hidden and 2nd one visible.
You could also use multiple screens and then just go back and forth between the 2 screens.