Add script to optimize PNG textures using optipng

tools/optimize-png-textures

@@ -0,0 +1,27 @@
+#!/bin/sh
+# Optimize all PNG textures using optipng, add them to Git index.
+# Run this script from the root of the repository for the effect.
+set -eu
+LANG=C
+
+PNG_FILES=$(find . -type f -name '*.png')
+
+get_png_size_total() {
+ cat ${PNG_FILES} \
+  |wc -c
+}
+
+PNG_SIZE_TOTAL_BEFORE=$(get_png_size_total)
+
+for PNG_FILE in ${PNG_FILES}; do
+ if git checkout "${PNG_FILE}"; then
+  printf '%s\n' "${PNG_FILE}"
+  optipng -o7 -zm1-9 -strip all "${PNG_FILE}"
+  git add "${PNG_FILE}"
+ fi
+done
+
+PNG_SIZE_TOTAL_AFTER=$(get_png_size_total)
+
+printf 'PNG size total before:\t%s\n' "${PNG_SIZE_TOTAL_BEFORE}"
+printf 'PNG size total after:\t%s\n' "${PNG_SIZE_TOTAL_AFTER}"