convert

webp

convert in.png webp:lossless=false out.webp

resize

convert in.png -resize 150x150 out.png

svg to png with transparent background

mogrify -background none -format png in.svg

batch

Converts all png files, resizes them and saves the result in subfolder webp:

mogrify -resize 1000x500 -format webp -path ./webp *.png