When I paste one image into another it does not appear. It just shows a blank box and you cannot see the picture. What's wrong?

When this problem occurs you will see something similar to what is shown in the image below. In this case the image of the state of Minnesota is being pasted onto an image of a monitor. The image of minnesota should be white with a black outline but all you see is a selcted region that has the same borders as the Minnesota image.

What you will need to do is go to the Layers, Channels, Paths, Undo Dialog/Dock. On it you will see the image that you just pasted labeled as "Floating Selection (Pasted Layer)", see screen shot below, you will need to rename this layer to something else.

To rename a layer double click on the name, which in this case was "Floating Selection (Pasted Layer)", and type in the new name. In this case we are naming it "Type in a New Name". Then click Enter on your keyboard.

As soon as you do this your image will then be displayed!