(resize png)

convert myimage.png -resize 50% myimage-small.png

(resize and ignore aspect ratio)

convert myimage.png -resize 100x100! myimage-square.png

(install imagemagick, image magic)

brew install ghostscript
brew install imagemagick

(imagemagick, caption, word wrap)

http://www.rubblewebs.co.uk/imagemagick/notes/wrap.php

(imagemagick, swap white for clear, replace with transparency)

convert image.gif -fuzz XX% -transparent white result.gif
source: https://www.imagemagick.org/discourse-server/viewtopic.php?t=12619

(imagemagick, old)

$ sudo port install ImageMagick
cool method called morph for switching images in gallery

(imagemagick, old, create new image of specific size)

create a new image of certain size
convert -size 512x512 xc:white ~/Desktop/foo.jpg