====== ImageMajick ======

===== How to use =====

Three commands:
  identify [options] filename.jpg
  display [options] filename.jpg
  convert input_file.jpg [options] output_file.jpg

Options:
  ‐background black  # default to white, used for letterbox
  ‐gravity center
  ‐resize 1920x1080  # scale down to fit, preserve aspect ratio
  ‐extent 1920x1080 # scale up to fit, preserve aspect ratio

Example:
  convert infile.jpg -gravity center -background transparent -resize 1920x1080 -extent 1920x1080 ou

Notes:
  * order of the keywords is significant, -gravity and -background must come before -extent
  * without -resize, with -extent only, the image will not be enlarged.

Example on multiplie files:
  find . -name "*.jpg" -exec convert {} -gravity center -background transparent -resize 1920x1080 -