Hello.
You have a slot named head with an image inside.
You duplicate it. So now you have a slot named head2 by default.
Then head2 is automatically selected. Proof, you can see the selection in the Hierarchy. It's highlighted.
But, if you move if with the translate tool, it's the original head that you moved. Not the head2 as you thought it would be. Sometimes it's boring when you start positioning images.
It works fine when you duplicate a bone, but not a slot.