magick

Convert jpg to png

1magick ${input}.jpg ${output}.png

Reduce jpg size by reducing quality

1quality=70
2magick ${input}.jpg -quality ${quality} ${output}.jpg

Reduce png size

1magick ${input}.png png8:${output}.png

Invert jpg colours

1magick ${input}.jpg ${output}.jpg -negate

Make jpg smaller

1magick ${input}.jpg -resize 25% ${output}.jpg

Trim images to border

1magick -trim ${image}.png ${output}.png

Make the white of an image transparent

1magick -transparent white -fuzz 10% ${input}.png ${output}.png

The 'fuzz' option tells the computer that 'close to white' is fine. You might want to use 20% or higher fuzz.

Give transparrent image a dropshadow

1magick ${input}.png \( +clone -background black -shadow 50x8+0+5 \) +swap -background none -layers merge +repage ${output}.png

Convert every jpg in directory to png

1mogrify -format png *.jpg

Convert from jpg to svg

1magick -flatten ${input}.jpg ${output}.ppm
2potrace -s ${output}.ppm -o ${svgout}.svg

Make an image showing day of the week

1magick -list font
2font="$(magick -list font | grep -oP 'Font: \K.*' | head -1)"
3
4magick -fill blue -font "${font}" -gravity center -pointsize 79 label:$(date +%A) day.png

Make a meme

1magick ${input} -font impact -fill white -pointsize 84 -stroke black -strokewidth 3 -gravity north -annotate +0+20 'TOP MEME TEXT' -gravity south -annotate +0+20 'BOTTOM MEME TEXT' ${output}