add three scripts

add imgcat imgchange and showxyz

imgchange.sh

@@ -0,0 +1,28 @@
+#!/bin/bash
+data='null'
+outdata='null'
+while getopts "hi:r" arg
+do
+	case $arg in
+		h)
+			printf "some commonly used tricks of imagemagick \n" 
+			printf "usage: ${0##*/} -i<image-file> [-r] \n"
+			printf "%s\t%s\n" "-i" "input image file"
+			printf "%s\t%s\n" "-r" "remove white background of the input image and apply a transparent background."
+			exit 0;;
+		i)
+			data=$OPTARG;;
+
+		r)
+			outdata=${data%.*}-nobg.png
+			convert ${data} -bordercolor white -border 1x1 -matte -fill none -fuzz 20% -draw 'matte 0,0 floodfill' -shave 1x1 ${outdata};;
+		?)
+			printf "error: unknow argument\nuse -h option to see help information\n"
+			exit 1;;
+	esac
+done
+
+if [[ $data == 'null' ]]; then
+	printf "error: no input file name\nuse -h option to see help information\n"
+	exit 1
+fi