The layers in your Photoshop file can be rearranged whenever you wish, either by dragging them in the Layers panel or by using keyboard shortcuts. Doing this alters the appearance of your artwork by changing which layers of it appear on top. The only exception to this is the background layer, if your file has one. This layer is locked at the bottom of the layer stack and cannot be moved unless you first turn it into a normal layer.
The Background Layer
The one thing that unequivocally identifies the background layer, if your image has one, is that its name is always Background and — unlike any other layer — is displayed in italics. The layer is always located at the bottom of the layer stack and also displays a lock icon. If you select the background layer, you can see that the blending and locking options at the top of the Layers panel are grayed out and inaccessible.
The fastest way of turning the background layer into a normal one is to click the lock icon. This changes its name to Layer 0 and makes it possible to change its position in the layer stack and make other changes, such as altering its opacity or its Blending mode. Alternatively, you can click Layer, hover over New and select Layer From Background, or simply double-click the layer's entry in the Layers pane. Doing either brings up a dialog box allowing you to type a name for the new layer, adjust its opacity and change its blending mode.
To turn a normal layer into the background layer, click Layer, hover over New and select Background From Layer. This option is only available if the image doesn't already have a background layer, and only when you have a layer selected in the Layers panel. The selected layer loses all transparency, with any transparent pixels being converted to whatever color you currently have set as the background color in the color picker, and drops to the bottom of the layer stack. This merging obeys whatever blending mode you had set for the selected layer — it acts exactly as if you'd placed the selected layer on top of a solid color layer and then merged the two.
To rearrange layers with your mouse, all you need to do is drag and drop them into position in the Layers panel. Note that the layer that gets moved is the one you click and drag, not the one you have selected, unless they are one and the same. To move multiple layers in the layer stack while maintaining their relative order, select all of them, and then click and drag any one of them.
Alternatively, select one or more layers in the Layer panel and then click Layer, hover over Arrange and select one of the commands in the sub-menu that appears:
Bring to Front pulls the layer or layers on top of the layer stack.
Bring Forward pulls the layer or layers up the layer stack by one layer.
- Send Backward drops the layer or layers down the layer stack by one layer.
- Send to Back drops the layer or layers to the bottom of the layer stack — but above the background layer, if one exists.
- Reverse is only available if you have more than one layer selected, and simply reverses their order in the layer stack.
A third option is to use keyboard shortcuts:
Alt-] is used to select layers, moving up the stack layer by layer with successive presses, starting either from the currently-selected layer or, if none is selected, from the layer at the bottom of the stack. Alt-] does the same, but moving down the stack with successive presses instead. Hold Shift as well to select multiple consecutive layers.
- Alt -. selects the layer at the top of the stack; Alt-, selects the layer at the bottom of the stack.
Ctrl-] moves the selected layers up the stack; Ctrl-[ moves them down the stack.
- Ctrl-Shift-] moves the selected layers to the top of the stack; Ctrl-Shift-[ moves them to the bottom of the stack.
If you've changed those keyboard shortcuts to something else, they won't work.
A Note About Layer Groups
Some of the commands used to rearrange the layer stack obey the boundaries of layer groups, while others don't.
- Using the commands in the Arrange sub-menu or keyboard shortcuts to move layers up or down the stack moves them in and out of groups if the layer group is open, but skips the group if it is closed.
- Using the Bring to Front or Send to Back commands — or equivalent keyboard shortcuts — on a layer that is inside a layer group sends it to the top or bottom of the layer group, not the entire layer stack.
- Dragging and dropping layers with your mouse can place layers anywhere in the stack — if you drop a layer on top of a closed group, Photoshop positions it at the bottom of the group.
Keep in mind that moving layers in and out of layer groups can have unintended effects on the overall appearance of your image if those groups are set to a blending mode other than Pass Through. This is because changing the blending mode for a group causes Photoshop to blend the layers inside it with each other first, and only afterwards blend the entire group with the rest of the image, using the blending mode you specified as if the group were a single layer.