Imagemagick
From Habitat: Giardino
Imagemagick
Basic
convert file.jpeg -resize 2000x2000 output-2000.jpg
Images are enlarged or reduced just enough so as to best fit into the given size.
convert file.jpeg -bordercolor yellow -border 50 output-border.jpg
Creates a yellow border of 50px
convert -charcoal 5 charcoal.jpeg
Charcoal effect. "5" is the value.
Tricks
Gray Scale
magick convert -set colorspace Gray -separate -average /path/to/my/file.jpeg export.jpeg
Monochrome
Return bitmap
magick convert -monochrome /path/to/my/file.jpeg export.png
Colors
The number of colours can be changed
magick convert /path/to/my/file.jpeg -dither FloydSteinberg -colors 3 export.png
magick convert /path/to/my/file.jpeg -colors 3 -colorspace gray -normalize
renders:
