2. Layer Operations
The Layers palette provides menu and shortcuts to manage layers in a Photoshop document. More details on these operations are explained in subsequent sections of this guide. In summary, we can change the properties of an existing layer, duplicate or add additional layers, delete existing ones, and rearrange the order of layers on the layer stack. If we make mistakes, the last operation can be discarded with the "Undo" options. A group of operations can be undone by removing the unwanted operations from the History palette.

The following is a brief summary of the functions performed by each icon present on the Layers palette. These functions and additional options are also available from the palette menu. They can be accessed by clicking the small triangle on the right side of the palette.

Add a layerstyle. Use this button (Or pressing F, or double click on the layer) to add a layer style by changing the current blending options such as shadow, gradient, outerglow, etc.. Add a layer mask. Use this button to create a mask four your selection. More details on selection & mask are covered in subsequent section. Create a new layer set. With this button you can add a new layer set to move existing layers or add more layers into it. This option is not available in older Photoshop version and can be very handy to organize documents with a large number of related layers. Create new fill or adjustment layer. Layers with predefined fill patterns, masks and colors can be created quickly with this option. Create a new layer. This option creates new transparent layer (no pixels). To duplicate an existing layer, click and drag the desired layer and drop it to this icon. The duplicated layer is created, placed on top of the dragged layer, and becomes the current layer. Photoshop assigns a name for the duplicated layer automatically. If you want to change the name of the new layer, right click to display the context menu which allow quick changes to the layer properties. Delete layer. This option deletes the current layer with confirmation. To quickly delete a layer without confirmation, drag the layer and drop it to this icon. Do not worry about deleting a layer or a group of layers by errors, since the last operation can always be undone with the "Undo" menu item or the History palette. Link a group of layers. A group of layers can be linked together so they can be moved or repositioned as a unit. Click the column to the left of a layer next to the layer's eye icon to link it to the current layer. When using the Move Tool and one of the linked layers is selected, all linked layers are moved as a unit.   Merge layers. Adjacent layers or a group of layers can be merged together to reduce the number of layers on the layer stack. Press Ctrl E or use the menu item Layers -> Merge Layers to merge the current layer with another adjacent layer beneath it. The current layer is removed from the layer stack and the contents of the merged layer replace the layer beneath. This operation behaves differently with linked layers. When merging a group of linked layers, all linked layers are merged and the result layer replaces the current (selected) layer.