GIMP
GIMP is a free, open-source raster graphics editor for retouching photographs, compositing images, and creating digital artwork.
Layers: Layers are stacked image components that can be edited and composited independently. GIMP layers let users combine artwork and adjustments while keeping components separate.
Photo manipulation: Photo manipulation alters photographs through retouching, compositing, or other image edits. GIMP supplies tools for repairing photographs and combining separate images.
Raster graphics: Raster graphics represent images as grids of colored pixels. GIMP edits pixel-based images, so resolution and pixel data shape its workflow.
Adobe Photoshop: Adobe Photoshop is a commercial raster graphics editor used for image editing and digital artwork. Photoshop is GIMP's best-known commercial counterpart, with different licensing and workflows.
Spencer Kimball: Spencer Kimball is an American software engineer who co-created GIMP as a student project. Kimball began GIMP with Peter Mattis at the University of California, Berkeley.
Layer mask: A layer mask controls which parts of a layer remain visible, using grayscale values. Masks make selective, reversible blending possible in GIMP composites.
Digital painting: Digital painting creates images using software tools that simulate or extend traditional drawing and painting. GIMP offers brushes, dynamics, and pressure-sensitive input for painted artwork.
Image resolution: Image resolution describes the amount of pixel detail in a digital image or its printed dimensions. Resolution affects the detail available for GIMP edits and the image's output size.
Krita: Krita is a free, open-source graphics application focused on digital painting and illustration. Krita emphasizes painting workflows, while GIMP serves a broader range of image-editing tasks.
Peter Mattis: Peter Mattis is an American software engineer who co-created GIMP with Spencer Kimball. Mattis helped establish the project and its early technical direction.