GIMP is highly flexible as its applications could be expanded and extended. It is designed to be augmented with plug-ins and extensions to do just about anything. The advanced scripting interface allows everything from the simplest task to the most complex image.

Manipulation procedures to be easily scripted. 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.
It has many capabilities. It can be used as a simple paint program, an expert quality photo retouching program, an online batch processing system, a mass production image renderer, an image format converter, etc.
Features and abilities
Full suite of painting tools including Brush, Pencil, Airbrush, Clone, etc.
Sub-pixel sampling for all paint tools for high quality anti-aliasing
Extremely powerful gradient editor and blend tool Supports custom brushes and patterns.

Tile based memory management so image size is limited only by available disk space
Virtually unlimited number of images open at one time
Advanced Manipulation
Full alpha channel support
Layers and channels
Multiple Undo/Redo (limited only by diskspace)
Editable text layers
Transformation tools including rotate, scale, shear and flip
Selection tools including rectangle, rounded rectangle, ellipse, free, fuzzy
Foreground extraction tool
Advanced path tool doing bezier and polygonal selections.
Transformable paths, transformable selections.
Quickmask to paint a selection.

A Procedural Database for calling internal GIMP functions from external programs as in Script
Script  Advanced scripting capabilities  with languages like Scheme, Python, Perl
Plug-ins which allow for the easy addition of new file formats and new effect filters over 100 plug-ins already available.
Load and save animations in a convenient frame-as-layer format
MNG support
Frame Navigator (in GAP, the GIMP Animation Package)
Onion Skin (in GAP, the GIMP Animation Package)
Bluebox (in GAP, the GIMP Animation Package)
File Handling
File formats supported include bmp, gif, jpeg, mng, pcx, pdf, png, ps, psd, svg, tiff, tga, xpm, and many others
Load, display, convert, save to many file formats
SVG path import/export
GIMP is written and developed under X11 on UNIX platforms. But basically the same code also runs on MS Windows and Mac OS X.
We have started to overhaul the default set of resources and in this version there have been some changes to the default set of brushes.
A plug-in for loading JPEG2000 images have been added, and also a plug-in for X11 Mouse Cursor files is also provided.
The projection code, the code that creates image from layers, have been ported to GEGL. This includes the layer modes. Refactorings  are  to prepare for adding support for nested layers,aka layer groups has also been performed, such as preparations for better and more intuitive handling of the floating selection.

You can use a tiny wrapper script called gimp-2.7 and place it into /usr/local/bin.