To flatten an image, first create a new Photoshop document by pressing Ctrl + N, or go to File → New. Open the image you want to flatten, then go to the menu above and hit Layer → Flatten Image. Once you hit this command, all your layers will be merged. Even if you have 10 or 20 layers, when you merge them, they will all become a single layer, an image. Now you can use the move tool “arrow” and move the whole image.

If you look to the right of your screen at the layer column, you will see only one layer listed. Flattening the image merges all the layers into one. Just like when you first open the document, because it only has one layer, it will be labeled Background and will have a little lock icon. You can unlock the icon by double clicking the lock icon. The image will continue to flatten even after you unlock the layer, and you won’t be able to modify the image or edit the text if you added one.

This does not mean that from now on you cannot modify it, only that you must first undo the image. To undo the flattening, go to Edit → Undo or press Ctrl + Z. This command will simply undo your last action. Previous layers will reappear, as they were before the flattening merged them.

Note that even if the “undo” command is the same, Photoshop will not allow you to do multiple undoes like Microsoft Word. If you keep pressing Ctrl + Z, you won’t undo your actions one by one. For this, Photoshop has a different command, called Step Back. So if you want to undo multiple steps, press Alt + Ctrl + Z.