Is the locked talisman used for something as of now? Also I am missing the 4th scene in the gallery, would you be able to tell me which one that is?
You'll need to buy the looking glass from the forest trader first. Then, don't visit Mona for 4 days and check her shop. If everything is alright, you'll find a note on her door. Then, find her in the forest zone close to the waterfall and get the scene.
No, the locket is an item one of my patrons wanted to make and doesn't serve any practical purpose.