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How to merge layers in Photoshop

If Photoshop keeps crashing while you're editing with a lot of layers, you may benefit from merging some of them. Learn how to merge layers and flatten your image with this how-to.
Written by Maria Diaz, Staff Writer
How to merge layers in Photoshop
Image: Maria Diaz / ZDNet

Since Photoshop works predominantly with layers, learning how to merge layers is useful when you need to make one layer out of several. This can be helpful when you have many image layers and Photoshop is either crashing or running slowly or you want to copy and paste an image quickly, without having to save it in a picture format beforehand. 

When you open a picture in Photoshop and edit the brightness and contrast, for example, an adjustment layer is created and added on top of the photo layer with the edit. So, if you need to copy that photo along with the brightness and contrast adjustment to paste it into another Photoshop window, you can do it quickly by merging them into one, enabling you to work with a single layer again.

How to merge layers in Photoshop

Step 1: Select layers to merge

Step 1: Select layers to merge

I selected the type layers on this document, we'll merge these and they'll work as one single layer

Image: Maria Diaz / ZDNet

Let's merge the type layers in this example, as well as the gray rectangles behind the letters. These include "FOR SALE," Rectangle 2 copy, "FIRE TV," and Rectangle 2. So we will select these four layers to merge.

Step 2: Merge layers

Step 2: Merge layers

Use either the menu or keyboard shortcut to merge the layers

Image: Maria Diaz / ZDNet

To merge these layers, you can press Ctrl+E (Cmd+E for Mac) or right-click (Control+click for Mac) on the selected layers and click Merge Layers.

The layers are merged into one

The layers are merged into one.

Image: Maria Diaz / ZDNet

When layers are merged, essentially they are flattened into a single layer, so you won't be able to work individually with them. Merging layers is best when you're already done working on those layers and still need to work with others in your file. 

To merge all the layers in your Photoshop document, select all the layers and right-click (Control+click for Mac) on the layers panel and select Merge Layers or, without needing to select them, use the shortcut Shift+Ctrl+E (Shift+Cmd+E for Mac).

Photoshop also has the option to merge visible layers. This will combine just the layers that are visible in the moment and leave others that have the visibility off, separated. Just right-click (Control+click for Mac) on the layers panel in Photoshop and select Merge Visible.

What's the difference between merging layers and flatten image?

Flatten Image or Merge Layers
Image: Maria Diaz / ZDNet

The difference is that flatten image will combine all the layers in the Photoshop document into one, while merging layers will let you either merge all layers, the selected layers, or only the visible layers. 

Does merging layers reduce file size?

Merging layers in Photoshop results in a smaller file size. While Photoshop runs as a well-oiled machine most of the time, working with a lot of layers at once, particularly image layers, can slow it down and make it prone to crashing, I've certainly been there before. It's a good idea to merge the layers you're done editing as you go to keep the program running smoothly.

Can you still edit after merging layers?

In a nutshell: Yes and no. You cannot edit type layers after they've been merged, for example, but you can edit over your image. This means that you can still add adjustment layers, filters, and use tools like cropping after you merge layers.

What's the fastest way to merge layers in Photoshop?

The fastest way is using the keyboard shortcuts: Ctrl+E to merge selected layers, Shift+Ctrl+E to merge all layers. 

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