Photo Editors
For convenience, here are some of the photo editors/graphic design programs used by the community.
It's not an exhaustive list nor a specific endorsement of any but provides some options to explore should you be in search of one.
The order of the list has no bearing on the quality or capabilities of an editor. Each has it's pros and cons and will appeal to different people, all are either free or have a free trial so you can give one a go and try another if find you don't get on with it.
Free
GIMP
An open-source advanced raster graphics editor initially released in 1995, a very capable program... if you can work out how to use it.
Platforms: Windows, macOS, Linux
Website: https://www.gimp.org/
Krita
An advanced open-source drawing and painting tool.
Platforms: Windows, macOS, Linux
Paint.net
A simpler raster graphics editor which is extensible through plugins. It gets things done but can be a bit limiting.
Platforms: Windows
Website: https://www.getpaint.net/
Photopea
A browser based editor for raster and vector graphics with support for various proprietary formats.
Platforms: Browser
Website: https://www.photopea.com/
Paid
Affinity Photo
An editor that closely competes with Photoshop while being available through a reasonably priced perpetual licence.
ℹ️ Affinity have been offering a 6-month free trial since their acquisition by Canva. They also offer a vector graphic equivalent.
Platforms: Windows, macOS, iPad
Licensing: Free Trial then Perpetual Licence
Website: https://affinity.serif.com/en-gb/photo/
ClipStudio
An advanced drawing and painting tool.
Platforms: Windows, macOS, Chromebook, iPad, Android, iPhone, Android Phone
Licensing: Free Trial then Subscription or Perpetual Licence (perpetual licence only available for Windows/macOS)
Website: https://www.clipstudio.net/en/
Photoshop
The Photoshop of photo editors, available through a rather expensive subscription which a lot of people seem to have no trouble with.
Platforms: Windows, macOS
Licensing: Free Trial then Subscription