I did used GIMP briefly as part of my web development projects and was really impressed with it. It’s one of the best alternative to Adobe Photoshop. And on top of everything it’s FREE. Yes you hard it right it’s free of cost and there is no harm in trying this amazing tool.
GIMP stands for GNU Image Manipulation Program. GIMP is a freely distributed program and works in different operating system such as Linux, Windows and Mac.
So if you are willing to try hand away from Adobe Photoshop due to reasons as it might be bit pricy or try new software then GMIP might be a good tool to try hands on.
GIMP can be used for various image manipulation, photo retouching and image authoring. It can be also used to created advanced stuffs like PSDs, Animations etc.
GIMP does also have a plugin repository where you can find various plugins and extension that might be useful to make your GIMP installation even powerful.
Basic Operations Using GIMP includes various image manipulations such as resizing, optimising images for web.
On advanced side, GIMP can be used to create Advanced Manipulation, PSDs and animations. Details can be found here.
GIMP Resources
Download GIMP - https://www.gimp.org/downloads/
Plugin repository - https://registry.gimp.org/popular
Tutorials - https://www.gimp.org/tutorials/
Feature Lists - https://www.gimp.org/features/