Batch convert images from png to jpg on a mac

pngTojpg.sh

#!/bin/bash

PNG_PATH=~/Desktop

shopt -s nullglob
png_files=($PNG_PATH/*.png)
shopt -u nullglob

for pfile in "${png_files[@]}"; do
  jfile="${pfile%.png}.jpg"
  echo "converting $pfile to $jfile"
  sips -s format jpeg "$pfile" --out "$jfile"
done