post images to a directory, set this script to watch the directory with cron

montage creation script

#!/bin/bash
# A simple script to create an album artwork montage

## move files to within montage directory w/ prepended unix timestamp
c_time=$(date +%s)
for f in `ls /tmp | grep "now_playing-"`
do
  mv /tmp/${f} /tmp/montage/${c_time}_${f}
  c_time=$(($c_time + 1))
done

## sort by last modified date, and remove all but the most recent 15 images
count=1
for f in `ls -r /tmp/montage`
do
  if [ $count -gt 15 ]
  then
    rm /tmp/montage/$f
  fi
  count=$(($count + 1))
done

## create montage image
montage -mode concatenate -tile 3x /tmp/montage/* /tmp/montage_result.jpg
cp /tmp/montage_result.jpg /var/www/ghost/content/themes/sticko/assets/images/sidebar_bg.jpg