Need help with a frame (beginner)

My frame consists of two door images, one open and the other closed.
What I would like is hotspot property instructions that makes the closed door turn into the open door image and then be able to pass through to go to the next frame.
I tried to figure out the "First person game WITHOUT scripting" hotspot properties that consists of 4 door images and want to make mine just with the 2 I have. The idea is to be able to just "Drop" the key on the keyhole hotspot and the open door image appears. I can't seem to get the hang of it. Any help would be greatly appreciated
What I would like is hotspot property instructions that makes the closed door turn into the open door image and then be able to pass through to go to the next frame.
I tried to figure out the "First person game WITHOUT scripting" hotspot properties that consists of 4 door images and want to make mine just with the 2 I have. The idea is to be able to just "Drop" the key on the keyhole hotspot and the open door image appears. I can't seem to get the hang of it. Any help would be greatly appreciated