GIMP

●GIMP is an acronym for GNU Image Manipulation Program .
● It is a freely distributed program for such tasks as photo retouching, image composition and image authoring.
● The terms of usage and rules about copying are clearly listed in the GNU General Public License.

● GIMP provides a comprehensive toolbox for
performing basic tasks such as selections,drawings, color picker, and many more. It provides many tools
within its toolbox.
● A tool is a way of operating on images. It indicates the specified action on hovering the cursor over the icon. A toolbox has several icons; each icon is a separate tool. To activate a tool, left-click on it or use key shortcuts.

Link

https://www.gimp.org/tutorials/