SVG icons
Inkscape https://inkscape.org/
Give the util a path to the SVGs and a size in pixels. The size is width by height
python3 ./utils/svg2png.py collections/basics 64
The conversion script uses CairoSVG to convert the input sources.
Icon sources
To generate icons.md run the icons2markdown.py in the utils folder.
python ./utils/icons2markdown.py . > icons.md