How do I open a layer in GIMP?

You can open an image as a new layer in GIMP using the "Open as Layers" command.

Here's how:

• Using the Menu: Navigate to File -> Open as Layers... in the image menu bar.
• Using Keyboard Shortcut: Press Ctrl + Alt + O (or Cmd + Option + O on macOS).

This will open a file dialog, allowing you to select the image you want to add as a new layer to your current GIMP project.

Keep in mind that this method adds an image as a new layer. If you want to work with existing layers from a different GIMP project, you will need to open that project first, and then copy/paste the layers into your current project.