Image Converter for Slack Emoji (128px) - Required: ImageMagick.

img-conv-for-slack-emoji

#!/bin/bash

set -e

echo -e "Image Converter for Slack Emoji\nNOTICE: The image will be overwritten."

if [ $# -lt 1 ]; then
	echo "USAGE:"
	echo -e "  ${0} IMG_FILE [IMG_FILE...]\n"
	echo "IMG_FILE:"
	echo -e "  Path of an image file. (e.g. foo.png)\n"
	exit 1
fi


for imgpath in "$@"; do
	echo "${imgpath}"
	mogrify -resize 128x128 -unsharp 2x1.4+0.5+0 -quality 100 -verbose $imgpath
	echo ""
done

echo "Done"
exit 0

Or just use an alias in bash/zsh:

alias slackmojify="mogrify -resize 128x128 -unsharp 2x1.4+0.5+0 -quality 100 -verbose"