GIMP's toolbox groups tools by function, and each tool's settings appear in the Tool Options dock beneath it — a panel you should keep visible, since it's where you change brush size, selection mode, opacity, and dozens of other per-tool settings. If you're still setting up the program, the installation guide and download page walk through getting GIMP running on Windows before you start exploring tools.
Selections define which pixels an edit affects. The Rectangle Select (R) and Ellipse Select (E) tools draw geometric selections, while the Free Select or Lasso (F) tool lets you draw freehand or click points for a polygon. The Fuzzy Select, or "magic wand" (U), grabs contiguous areas of similar color, and Select by Color (Shift+O) grabs matching color anywhere in the image. The Intelligent Scissors and Foreground Select tools are better suited to cutting out subjects with irregular edges. Holding Shift while selecting adds to the current selection, and Ctrl subtracts from it.
The Paths tool (B) creates precise vector-style curves using anchor points and Bezier handles, similar to a pen tool in other editors. Paths can be stroked with a brush, converted into a selection, or saved and re-edited later, which makes them useful for clean cutouts and smooth custom shapes that selection tools alone can't achieve easily.
The Move tool (M) repositions layers, selections, or paths. Scale (Shift+T), Rotate (Shift+R), Shear, and Perspective transform a layer's content, and the Crop tool (Shift+C) trims the canvas itself. The Unified Transform tool combines several of these into one interactive handle set, which saves switching tools mid-edit for compositing work.
GIMP's paint tools share a common set of brush, size, and opacity controls but behave differently on the canvas:
N) draws hard-edged strokes with no anti-aliasing, useful for pixel art.P) applies soft, anti-aliased strokes and is the default choice for general painting.A) builds up color gradually the longer you hold the mouse or pen in place, mimicking a spray can.K) simulates a calligraphy nib with an angled, pressure-responsive tip.Y) bring in a separate, highly configurable brush engine popular with digital painters, with textures that react naturally to tablet pressure and tilt.The Clone tool (C) copies pixels from one part of an image to another, sampled from a source point you set with Ctrl+click, and is the standard tool for removing blemishes or duplicating elements. The Heal tool works similarly but blends the sampled texture into the surrounding color and lighting automatically, which usually gives a more seamless result on skin or sky. Blur/Sharpen (Shift+U) softens or crisps up small areas under the cursor, and Smudge (Shift+S) drags pixels like wet paint — both are best used at low opacity for subtle retouching rather than global corrections.
The Gradient tool (G) draws a smooth transition between two or more colors along a line you drag across the canvas, with several gradient shapes and blend modes to choose from. Bucket Fill (Shift+B) fills a selection or contiguous color area with the foreground color or a pattern in one click, and its threshold setting controls how strictly it matches adjacent pixel colors.
The Text tool (T) creates editable text layers with font, size, and alignment controls in Tool Options. The Color Picker (O) samples a pixel's exact color and loads it as the foreground color, which is handy for matching tones during retouching. The Measure tool calculates distance and angle between two points on the canvas, useful for straightening scanned images or checking proportions before you crop.
Every tool's settings live in the Tool Options dialog, normally docked under the toolbox on the left side of the window. If it's ever closed, reopen it from Windows > Dockable Dialogs > Tool Options. Because these settings persist per tool, switching between the Paintbrush and the Eraser, for instance, keeps each tool's last-used size and opacity remembered separately, which speeds up repetitive retouching work.
GIMP ships with parametric and bitmap brush sets, adjustable for size, hardness, spacing, and angle from the Brushes dockable dialog. You can import third-party brush packs in GIMP's own format or as image-based brushes, and the separate MyPaint brush engine adds another library entirely, aimed at natural-media painting with tilt and pressure response on a graphics tablet.
Beyond the core paint and selection tools, the Filters menu extends GIMP considerably — blur and sharpen filters, distortion effects, noise reduction, and generative patterns are all built in. Community plug-ins add further capabilities, from content-aware fill to specialized batch-export scripts, and can be installed by dropping them into GIMP's plug-ins folder. For a broader look at what these filters can do alongside the core toolset, see the GIMP features overview, and for applied examples check the photo editing and drawing guides.