Creates a twitter sized image filling in the background with the dominate image color

create_twitter_image.sh

#!/bin/bash
export PATH=/usr/local/bin/:$PATH

for f in "$@"
do
hexcode=$(convert "$f" -format %c -depth 8 histogram:info:- | sort -n | tail -1 | awk '{ print $3 }')
convert "$f" -resize 1600x900 -background "$hexcode" -gravity center -extent 1600x900 "$f".twitter.png
done