Editing images

Chinks in my armour of learned photoshop helplessness

See also colour, diagrams etc.

Command line image editing

Two command line tools to remember are graphicsmagick and imagemagick — two similar, stand-offish rivals. Imagemagick is the “original” whatever that means in the confusing phylogentical world of software. Graphicsmagick has, AFAICT, a better API. They are often farily interchangeable from a user perspective.

G'MIC includes a whole world of image conversion including scriptable image processing pipelines. See, e.g., a hand-rolled fingerpainting filter. Also has GIMP and Krita plug-in versions.

imagemagick hacks

[Fred Weinhaus’s imagemagick scripts) show you how to do a great many useful things, e.g. Histogram matching. (⚠️ Beware the odd licensing conditions.)


Old school:

convert favicon.png  -bordercolor white -border 0 \
      \( -clone 0 -resize 16x16 \) \
      \( -clone 0 -resize 32x32 \) \
      \( -clone 0 -resize 48x48 \) \
      \( -clone 0 -resize 64x64 \) \
      -delete 0 -alpha off -colors 256 favicon.ico


convert favicon.png -define icon:auto-resize=64,48,32,16 favicon.ico


GUIs? you want, e.g. the adobe suite, which I will never touch because of the economics of comparative advantage…

Or a weird alternative one.


Gimp is a flagship open source image editor. It has powerful plugins. Its user experience is a clusterfuck; there are such startling and unneccessary pain points as the fact that plugin registry (which is IMO the only reason you would want to dive into this dorknado) is broken in an undocumented way that probably has to do with it being am undermaintained security nightmare.

Paul Harrison’s rsynthesizer 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


Krita is a ground-up reimagining of fun open-source non-nerview 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.