Free, open-source alternatives to Adobe Photoshop

Photoshop is a raster image editor built around layers, selections and masks, used for photo retouching, compositing and general graphics work. The open-source apps below cover that same core job: opening an image, editing it in layers and exporting the result.

GIMP is the broadest of the three for photo work, with a deep set of selection, painting, colour and filter tools plus support for plug-ins and scripts. Krita is built first for digital painting and illustration, but its layers, masks, selections and filters also handle general raster editing. Seashore is a smaller native Mac editor aimed at everyday layer work rather than professional retouching.