when i drop a new photo into Photoshop on top an existing photo it does not show up in the layers panel with the first photo. I can click on one photoit shows up in the layer panel, but i cannot get them both to show up at once to be able to work on them. Example: I want to replace sky in one photo. When I drop a replacement sky into photoshop it will not show up in the layers panel under the first photo. They will only show up one at a time which ever one I clicked on.