The GIMP is the GNU Image Manipulation Program. It is used to edit and manipulate images. It can load and save a variety of image formats and can be used to convert between formats.

Gimp can also be used as a paint program. It features a set of drawing and painting tools such as airbrush, clone, pencil, and paint brush. Painting and drawing tools can be applied to an image with a variety of paint modes. It also offers an extensive array of selection tools like rectangle, ellipse, fuzzy select, bezier select, intelligent scissors, and select by color.

Gimp offers a variety of plugins that perform a variety of image manipulations. Examples include bumpmap, edge detect, gaussian blur, and many others.

In addition, Gimp has several scripting extension which allow for advanced non-interactive processing and creation of images.
OPTIONS
The gimp accepts the following options:

-h, –help
Display a list of all commandline options.
-v, –version
Output the version info.
-b, –batch
Execute the set of non-interactively. The set of is typically in the form of a script that can be executed by one of the Gimp scripting extensions.
-g, –gimprc
Use an alternative gimprc instead of the default one. Useful in cases where plugins paths or machine specs may be different.
-i, –no-interface
Run without a user interface.
-r, –restore-session
Try to restore saved session.
-d, –no-data
Do not load patterns, gradients, palettes, or brushes. Often useful in non-interactive situations where startup time is to be minimized.
–verbose
Show startup messages.
–no-shm
Do not use shared memory between GIMP and its plugins. Instead of using shared memory, GIMP will send the data via pipe. This will result in slower performance than using shared memory.
–no-xshm
Do not use the X Shared Memory extension. If GIMP is being displayed on a remote X server, this probably needs to be enabled. Also useful for any X server that doesn’t properly support the X shared memory extension. This will result in slower performance than with X shared memory enabled.
–display display
Use the designated X display.
-s, –no-splash
Do not show the splash screen.
-S, –no-splash-image
Do not show the splash screen image as part of the splash screen.
–debug-handlers
Enable debugging signal handlers.
-c, –console-messages
Do not popup dialog boxes on errors or warnings. Print the messages on the console instead.
–enable-stack-trace {never|query|always}
If a stack-trace should be generated in case of fatal signals.
–system-gimprc
Use an alternate system gimprc file.