Editing images using a GUI

1 Pinta

A tiny, simple one. Pinta: Painting Made Simple.

Pinta is a free, open-source program for drawing and image editing.

Its goal is to provide users with a simple yet powerful way to draw and manipulate images on Linux, Mac, Windows, and *BSD.

You can write extensions in C#.

2 Gimp

Gimp is a flagship open-source image editor. It has powerful plugins. Its user experience is a clusterfuck; there are such startling and unnecessary pain points as the fact that the plugin registry (which is a popular selling point of this dorknado) is broken in an undocumented way that probably has to do with it being an undermaintained security nightmare.

Paul Harrison’s resynthesizer is a texture synthesizer for GIMP. See also his rather amazing thesis, with a diversion into the Turing completeness of tiling. And yes, that G’MIC thing is also gimpy.

3 Krita

Krita is a ground-up reimagining of fun open-source non-nervy image editing. It has cute features like quasi-physical-modelling brush design and automatic tiling mode. Fairly pleasant to use. You can write your own plugins in Python, making this an art python app.

4 ImageJ

Classic “scientific” editor ImageJ has been useful for a decade or two. I think the most popular distribution is Fiji. ImageJ2 is the core:

ImageJ2 is a rewrite of ImageJ for multidimensional image data, with a focus on scientific imaging. Its central goal is to broaden the paradigm of ImageJ beyond the limitations of the original ImageJ application, to support the next generation of multidimensional scientific imaging.