PNGQuanter, Nautilus script that calls PNGQuant from Nautilus's 'script' menu

PNGQuanter

#!/bin/bash

# AUTHOR:		Ronan Jouchet <ronan@jouchet.fr>, based on another author-less Nautilus script
# VERSION:		1.0
# LICENSE:		MIT
# REQUIRES:		-
# NAME:			PNGQuanter
# DESCRIPTION:		Reduce size with a call to pngquant
# INSTALL:		Put script in ~/.local/share/nautilus/scripts and ensure it's executable

# Check that the user didn't select directories
for File in "$@"
    do
    if [ -d "$File" ]; then
        zenity --error --text="'$File' is a directory.
        PNGQuanter cannot handle directories."
        exit
    fi
done

# Use trash-put (provided by trash-cli) if present, else just rm
if which trash-put >/dev/null; then
    pngquant "$@" && trash-put "$@"
else
    pngquant "$@" && rm "$@"
fi