When comparing GIMP vs Pixly, the Slant community recommends GIMP for most people. In the question“What are the best pixel art / sprite editors?” GIMP is ranked 4th while Pixly is ranked 14th. The most important reason people chose GIMP is:
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](http://www.gimp.org/source/).
Specs
Ranked in these QuestionsQuestion Ranking
Pros
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.
Pro Powerful
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.
Pro Lightweight
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.
Pro Beginner-friendly
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 Color selector with different color systems
RGB, CMY, HSB, and a somewhat different HUSL.

Pro Offers color ramp generator
Pixly offers a color ramp generator that then exports directly into a custom palette.

Pro You can use reference images
You can work with a reference image on top of your art, or by its side.

Pro Allows you to continue your work even when not in front of your PC
This tool works on both phones and tablets that run Android, which is handy for when you do not have access to a PC.

Pro Layered projects

Pro Gestures that feel natural on touch screens
In Pixly, you can move the art around with two fingers (like in Google Maps) and change the brush/eraser size with a three-finger pinch.

Pro Supports onion skinning
Onion skinning is also called ghosting. It allows the user to see the past and previous frames, while editing the current frame. This way, the user can make decisions on how to create or change an image.

Pro Mirroring support
In Pixly, the user can make symmetrical art with a mirror, or even go bananas setting up two or more mirrors at different angles at once.

Pro Transparency support
The user can make transparent sprites in Pixly.

Pro Animation support
Even though this is a mobile tool, it's fully featured and even allows you to create animations.

Pro Standard and custom palettes

Pro Live image tiling
The user can create tiles in Pixly and keep an eye on progress in real time.

Pro Color filters
Cons
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 No PC version
The PC version has not yet been released.
