When comparing GIMP vs GrafX2, the Slant community recommends GrafX2 for most people. In the question“What are the best pixel art / sprite editors?” GrafX2 is ranked 3rd while GIMP is ranked 9th. The most important reason people chose GrafX2 is:
GrafX2 is scriptable using the Lua language, which can be used to automate tasks and add new functionality to it. The script library features advanced color reduction and enhancement tools, [palette analysis](http://eab.abime.net/showthread.php?t=76519), and much more.
Ranked in these QuestionsQuestion Ranking
Pro Free, open source and cross-platform
GIMP is completely free and open source, meaning you can use GIMP and all of its features without spending a penny. This makes it an excellent case for artists or designers who may not have the budget to spend over 700 USD on Photoshop. It is also available for free on Windows, Mac OS and Linux. It's licensed under GPL with source code available here.
GIMP is the most feature rich free image editing tool. It has most image manipulation and workflow tools that you would expect from an image editing software and what it lacks it makes up with plugins.
Pro Content-aware tools with a plugin
There's a content-aware fill plugin available for GIMP.
Pro Modular & single-window interface options
By default GIMP splits out each window, but you can check to use the one screen mode in options if you prefer.
Compared to to other photo editing software, GIMP is very light weight. In addition it isn't very resource-intensive, meaning you can put it on a flash drive and have it with you to load up on just about any computer.
Gimp has less features than programs like Photoshop, but for a beginner, or someone not needing complicated options, Gimp is the perfect choice. It allows you to quickly do basic photo manipulation so you can easily get the product you need without having to worry about complicated features getting in the way.
Pro Full channel support
Pro Scriptable using Lua
GrafX2 is scriptable using the Lua language, which can be used to automate tasks and add new functionality to it. The script library features advanced color reduction and enhancement tools, palette analysis, and much more.
Pro Supports many file formats
GrafX2 supports many file formats, including the popular gif and png, but also importing and exporting from deluxe paint, degas elite, and various other editors using custom formats.
Pro Very large number of tools and effects
Pro Free, open source, and cross-platform
GrafX2 is totally free to use, copy, and modify. It's available on Windows, Linux, Mac OS X, Haiku, AROS, MorphOS, SkyOS, Syllable, Mint, and a few more systems. Basically anything is supported by the SDL library.
Pro Palette color cycling
GraphX2 being based on older 256 bitmap software has inherited some tricks that modern pixel editors do not have . One of them being the ability to cycle color palette and produce animations and effects with it.
Pro Has a great palette tool
You can create gradients from one color to another, work in either RGB or HSL color space, save and load palettes, sort and organize palettes, and even work on "color cycling" images.
Pro Supports tileset addition and extraction
Pro Supports animations
The program has a basic support for animation using frames in newer versions. Graphics can be cloned and copied between frames and changed slightly.
See here how to animate with GrapfX2 https://www.youtube.com/watch?v=Gnq6zBZOqoM
Pro Has a customizable UI with themes support
Theme UI style can easily be changed from settings including buttons and colors.
Pro Drawing constraint mode for vintage 8bits machine
The program is able to enforce the pixel constraints of old machines (C64, ZX Spectrum, Apple II, Game Boy Color, etc.)
For example, in ZX Spectrum mode, only 2 different colors can be used in a 8x8 pixel block.
Con Unintuitive interface
GIMP doesn't embrace OS X application design, thus Mac users might have a hard time wrapping their heads around GIMP's interface.
Con Less features than other programs
Being a free program, it shouldn't be surprising that it has limited features. For those needing more advanced features for something more professional, GIMP just isn't for you.
Con Lacks adjustment layers
Adjustment layers offer a non-destructive way of combining different photo manipulations. Without adjustment layers the only way to see changes is by irreversibly editing the image.
They are promised in future updates.
Con Poor performance
Con Dated look and feel
It looks like it was never supposed to be used in the modern world.
Con Lack of modern features
Some modern features that are necessary to do pixel art creation for game dev work are lacking.