When you are working on a document with a number of layers and you want to select a certain layer, you could switch to the Move tool, hunt for, and click on the layer. But you can save time and effort when you are working with a different tool by simply pressing Ctrl Alt Click (Mac: Cmd Opt Click) on the image. The layer under the spot that you click will be automatically selected. You’ll see it highlighted in the Layers panel.
So if you are using a tool like Dodge or Burn or the Brush tool to make adjustments to several photos on a page, for example, you won’t have to change tools and search for the next photo. Just Ctrl Alt Click (Cmd Opt Click) to select it quickly and continue your adjustments.