GIMP is a free, open-source image editor for Windows, macOS and GNU/Linux. It combines photo correction, retouching and layered image composition with tools for painting and creating graphics. A project can hold photographs, painted details, editable text and vector shapes as separate parts of the same image.
GIMP’s photo retouching tools
GIMP’s photo tools address both the framing of a picture and the pixels within it. Rotation straightens tilted subjects, while cropping defines the visible area. Cropped pixels can be retained outside that area, allowing the framing to be reconsidered later.
Levels sets the black point, white point and midtones using controls beneath a histogram. Curves offers finer control by mapping input brightness to output brightness through points on a graph. These adjustments can also target individual color channels to change a color cast, while Hue/Saturation changes the hue, lightness and saturation of colors.
For local repairs, the Clone tool paints pixels taken from another area of the picture or another image. The Healing tool also considers the area around the destination, helping a repair fit into the surrounding texture. Brush size and the chosen source area determine how much detail is replaced. Sharpening filters strengthen apparent edge detail, with adjustable strength that also affects how much noise becomes visible.
Layers, selections and masks
A GIMP composition is assembled from layers that can be moved and edited independently. The layer stack determines which elements appear in front, opacity controls how strongly each contributes, and blend modes change how its colors combine with those beneath it. Groups keep related components together in a complex image.
Selections restrict most edits to a chosen region. Feathering spreads the transition across an adjustable distance, so a pasted subject or local correction can have a gradual edge. Quick Mask displays the selection as an overlay, making partially selected areas easier to see than the dashed selection boundary alone.
Layer masks provide a separate grayscale surface for controlling transparency. Painting on a mask changes which parts of the associated layer show through, while keeping its image content separate from the visibility adjustment. This supports composites in which an edge needs repeated refinement as the surrounding layers change.
Layer effects
Eligible GEGL filters can remain attached to a layer as editable effects. Their settings can be reopened, their visibility switched off, and their order changed without replacing the underlying pixels. Order matters because each effect receives the result of the effects processed before it.
These effects remain editable when the project is saved in GIMP’s XCF format and reopened. Merging a filter instead commits its result to the layer’s pixels.
Brushes
Painting tools share a brush collection for drawing, erasing, smudging and other operations. A stroke places a series of brush marks along its path; brush size and spacing change the marks and the distance between them. Grayscale brushes use the selected foreground color, while color brushes keep the colors of their source image.
GIMP can create brushes from image content, including a copied selection, and its brush editor generates adjustable shapes. The MyPaint Brush tool provides another painting engine. On supported tablets it can use stylus pressure and barrel rotation, while a Gain control changes pressure strength or simulates it when painting with a mouse.
Text, vector and link layers
Text stays on its own editable layer, with controls for its appearance and outline. Vector layers add shapes based on paths: changing the path changes the shape, while fill, stroke color and line width remain adjustable. These shapes can be scaled, rotated and transformed without first becoming a painted collection of pixels.
Link layers bring an external image into a composition and update when that source image changes. For example, a separately edited logo can remain connected to a larger layout. Text, vector and link layers require an explicit rasterization operation before destructive painting; reverting that operation restores the editable layer type and clears the destructive edits.
Color profiles
GIMP uses ICC profiles to interpret image colors and display them through a monitor profile. An imported image can keep its embedded profile or be converted to a working color space. If its profile is missing, a known profile can be assigned separately.
Soft proofing uses a printer profile to simulate printed colors on screen. It can mark colors outside the destination’s reproducible range, giving the editor a way to identify areas that may change in print.
Image export
Saving to XCF retains the layered project and its editable effects. Export creates a file for another application or destination, such as a JPEG photograph or PNG graphic. Exporting leaves the open project intact, although the output format determines which image properties survive; editable effects are rendered into the exported result.
JPEG export includes a quality control with a preview, allowing compression changes to be judged against the image. Metadata inclusion can also be selected where the destination format supports it.
Plug-ins
Plug-ins run under GIMP’s control and can manipulate images opened in the editor. They extend image operations and file formats, while Python and Scheme support scripted image manipulation.
