USE LAYERS!
Disciplining oneself to use layers properly will save a lot of grief in the long run.
Layers can be thought of as transparent sheets of film in a stack, which can be sorted, switched on (visible) and off and locked at will.
The very first step on importing an image is to copy it to another layer, lock it and make it invisible. You can then always go back to the original without saving it as a different file!
Each significant edit, added text etc should all be on separate layers and can then be viewed / edited independently.
Just my 2c ....
Cliff