added script

convert.sh

@@ -0,0 +1,36 @@
+#!/bin/bash
+shopt -s globstar
+
+size=16
+
+for i in src/**/*.{png,gif,jpg}; do
+    echo "$i"
+    absDirname=$(dirname "$i")
+    origFilename=$(basename "$i")
+    browserCode=${origFilename%.*}
+    dirname="dist/${absDirname#src/}"
+    distFile="${dirname}/${browserCode}.png"
+    echo "$distFile"
+    if [ ! -d "$dirname" ]
+    then
+        mkdir -p "$dirname"
+    fi
+    convert \
+        "$i" \
+        -transparent white \
+         -background none \
+        -trim \
+        -resize ${size}x${size} \
+        -gravity center \
+        -extent ${size}x${size} \
+        "$distFile"
+        # input file
+        # make background transparent
+        # keep transparency
+        # cut border
+        # resize while keeping the aspect ratio
+        # center image
+        # fit to 16x16
+    # optimize png:
+    optipng -o 9 -q "$distFile"
+done