#!/bin/bash

for file in `find . -type f -iname "*.png"`
do
    echo -n "processing $file ... "

    isWhite=`convert $file -colorspace HSL -channel g -separate +channel -format "%[fx:mean]" info:`

    if [ "$isWhite" == "0" ]
    then
        rm $file
        echo "removed"
    else
        convert $file -bordercolor white -border 1x1 \
                -alpha set -channel RGBA -fuzz 10%   \
                -fill none -floodfill +0+0 white     \
                -shave 1x1 $file

        convert $file -channel rgba -alpha set -fuzz 10% -fill none -opaque white $file
        echo "converted"
    fi
done