Merge and stamp layers

When you have finalized the content of layers, you can merge them to reduce the size of your image files. When you merge layers, the data on the top layers replaces any data it overlaps on the lower layers. The intersection of all transparent areas in the merged layers remains transparent.

Note: You cannot use an adjustment layer or fill layer as the target layer for a merge.

In addition to merging layers, you can stamp them. Stamping allows you to merge the contents of more than one layer into a target layer while leaving the other layers intact.

Note: When you save a merged document, you cannot revert back to the unmerged state; the layers are permanently merged.

Merge two layers or groups

Make sure that the layers and groups you want to merge are visible.
Select the layers and groups you want to merge.
Choose Layer > Merge Layers.

Note: You can merge two adjacent layers or groups by selecting the top item and then choosing Layer > Merge Down or Merge Group. You can merge linked layers by choosing Layer > Select Linked Layers, and then merging the selected layers.

Merge layers in a clipping mask

Hide any layers that you do not want to merge.
Select the base layer in the clipping mask. The base layer must be a raster layer.
Choose Merge Clipping Mask from the Layers menu or the Layers palette menu.

For more information on clipping masks, see Mask layers with clipping masks.

Merge all visible layers and groups in an image

Choose Merge Visible from the Layers palette or the Layers palette menu. All layers showing an eye icon are merged.

Note: A visible layer must be selected to enable the Merge Visible command.

Stamp multiple layers or linked layers

When you stamp multiple selected layers or linked layers, Photoshop creates a new layer containing the merged content.

Select multiple layers.
Press Ctrl+Alt+E (Windows) or Command+Option+E (Mac OS).

Stamp all visible layers

Turn visibility on for the layers you want to merge.
Do one of the following:
- Press Shift+Ctrl+Alt+E (Windows) or Shift+Command+Option+E (Mac OS).
- Hold down Alt (Windows) or Option (Mac OS), and choose Layer > Merge Visible.
Photoshop creates a new layer containing the merged content.

Flatten all layers

Flattening reduces file size by merging all visible layers into the background and discarding hidden layers. Any transparent areas that remain are filled with white. When you save a flattened image, you cannot revert back to the unflattened state; the layers are permanently merged.

Note: Converting an image between some color modes flattens the file. Save a copy of your file with all layers intact if you want to edit the original image after the conversion.

Make sure that all the layers you want to keep are visible.
Choose Layer > Flatten Image, or choose Flatten Image from the Layers palette menu.

Photoshop