GIMP

A scanned family photo looks fine until you zoom in and meet every speck of dust from the last forty years. Scratches and dust like these have to be repaired one spot at a time, without touching the rest of the picture. GIMP handles that kind of retouching and restoration on the desktop, and it also builds composites out of several images. Parts of a picture can sit on separate layers, so changes stay apart until you merge them.

Version 3.2 added layer types that stay editable: a link layer shows an outside file, like an SVG drawn in Inkscape, and updates when that file changes. Vector layers hold shapes as paths, so they can be resized without losing sharpness, and filters can be changed or removed after they are applied.

Illustrators get MyPaint brushes that follow canvas zoom and rotation, plus a paint mode made for pixel art. For print work, GIMP manages color across screen and paper, and its CMYK color picker shows total ink coverage. The site places it in a publishing workflow next to the open-source programs Scribus and Inkscape.

Repeated edits can be scripted in Python or Scheme, and third-party plugins add further tools. GIMP exports to PSB, the Photoshop format for very large files, and to SVG and PDF with the layer data kept. It is a community project, released under the GNU General Public License.