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I often bracket my photos then go to align them, or use the auto align feature for many other things. But one thing I could never work out was how to choose which layer doesn't move. I've tried googling, no one seems to know, I've tried locking a layer, putting it on top, on the bottom, selecting it first, last, no matter what I do photoshop seems to just want to decide by its self. So how do I do this? How do I chose the layer that doesn't move when I use auto align?