Image Ed "j" key swap slots question

When I hit the “j” key, it swaps from slot 1 to slot 2 and then to slot 3. I only want it to swap from slot 1 to slot 2. Is that possible to set up? I keep having to cycle through an empty slot 3 to view slot 1 and 2 changes.

You could use Alt+J to go to the previous slot. J = forward, Alt+J = back