GIMP
De DMS

GIMP (GNU Image Manipulation Program) is an image retouching and editing tool[4] and is released under the GPLv3 license as free and open-source software. There are versions of GIMP tailored for most operating systems including Microsoft Windows, Mac OS X and Linux.
Guide
Démarrage
Cliquez sur l'icône correspondant au logo (dans la barre du haut) ou entrez plutôt la commande
gimp
dans un terminal.