What is Image Masking? Image masking is a technique used in photo editing to isolate or remove specific parts of an image. This is often done by creating a mask, which is a grayscale image that defines which parts of the original image should be visible and which should be hidden. With image masking, you can selectively hide or reveal parts of an image, making it an essential tool for photo editing. It allows you to remove backgrounds, change colors, and multiple composite images together to create a single image.