Working with Layers
One of Photoshop's most powerful features is its use of layers. Each layer is basically a separate image which can be edited without making changes on all the others.
The neat thing about the move tool is that it has a built-in layer navigation so Photoshop can determine the layers beneath an area in the image. When you press CTRL + right click, a menu will pop up displaying the names of the layers in order, from top to bottom (see image on the right). To select the layer you want to move, highlight that layer in the popup menu and drag.
If you have multiple layers on your image, one of the problems you will encounter is that you won't be able to move multiple layers at the same time. Thankfully, there are several workarounds available for this. By default, the layers window should already be on the low right corner of your workspace (see photo on left). If you don't have it yet, click on ALT + W and choose layers to activate the layers palette.
To select multiple layers, press CTRL and choose the layers you want. Now click on the document window and drag. This should move the layers you have selected. Note however that this only works if there are no active selections on the image.
If you wanted to duplicate your layers, you can just click the new layer icon on the layers palette (see photo above) or select duplicate layer from the layer menu. If you have several pixels selected, pressing CTRL + J will duplicate those pixels.
You will also have an option to merge layers without having to delete all the other layers. To do this, just select merge in the layers menu or press CTRL + SHIFT +ALT + E. Make sure to create a new layer before you do this so that the merged layers will end up in a separate layer and would allow you to revert your changes without any trouble.
If your right click on a selection, the option to copy will only apply to the selected layer. If you want to copy all the visible layers, choose copy merged instead. The keyboard shortcut for this is CTRL + SHIFT + C.
If you had to paste pixels into an image, this will automatically create a new layer. You can also choose to paste into (CTRL + SHIFT + V) or paste behind (CTRL + SHIFT + ALT + V) will allow you to create a layer and a layer mask in just a couple of steps.
If you want to copy pixels or a layer to another document, just drag it from the source document and drop into the target image so you wont have to use the clipboard (to avoid wasting your RAM). Remember that the image will be placed on the exact spot where you dropped it. Hold down the SHIFT key to center the selection in the new image. If the target image has the same pixels as the source, pressing the SHIFT key will place the copied pixels in the exact place as in the original document.
On the next page, you will learn how you can use layers and the move tool to align and distribute elements.