When I scrapbook with paper and adhesive, I have two choices: Removable or Permanent tape. In Photoshop and PSE, I have the same two choices.
Linking layers is the digital equivalent of repositionable glue. To link two or more layers, hold the Ctrl (Mac: Cmd) key and click on the layers you want to link. Release the Ctrl (Cmd) key and click the chain link icon above (PSE) or below (PS) the Layers Palette. Now the layers will stick together like glue and can be resized or repositioned together. To unlink the layers, simply select the layers you want to unlink and press the chain link icon again.
Merging Layers is the digital equivalent of Super Glue. Once you merge layers, you canít undo it without going back a step or more in the History Palette. If youíve completed a number of steps, this can cost you precious time, so make sure that you really want the layers together as one before you merge. To Super Glue two layers together, stack the layers one on top of the other and highlight the upper layer. Press Ctrl + E (Mac: Cmd + E) on your keyboard. This glues the two layers together.
To Super glue several layers together, hold the Ctrl (Mac: Cmd) key to select all of the layers you are merging and press Ctrl + E (Mac: Cmd + E).