Dual screen wallpapers with hourly random change (gnome/mate)

generate.sh

#!/bin/sh

# Drop all your images in a folder, let's call it /tmp/wallpapers then run this
# Take all your files from the output folder and put them somewhere in your
# home folder (like ~/Pictures/Wallpapers)
RES=$( xrandr | grep primary | awk '{ print $4 }' | cut -d '+' -f 1 )

mkdir output 2>/dev/null
for a in *.{png,jpg,tga}; do
  for b in *.{png,jpg,tga}; do
    [[ "$a" != "$b" ]] && \
    [[ -f "$a" ]] && \
    [[ -f "$b" ]] && \
      echo "Merging $a and $b" && \
      convert \
        "$a" -resize "${RES}^" -gravity center -crop "${RES}+0+0" +repage \
        "$b" -resize "${RES}^" -gravity center -crop "${RES}+0+0" +repage \
         +append "output/${a}-${b}";
    # allows us to ctrl+c more easily
    sleep 0.1;
  done;
done;

randomize.sh

#!/bin/sh

# Change the variables up there and set this as a @hourly cronjob

UID=1000
USER=crobin
DISPLAY=:0
DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/${UID}/bus
GCONF=$( hash dconf && echo dconf || echo gconf )
RANDOM_WALLPAPER=$( /usr/bin/ls -1 /home/${USER}/Pictures/Wallpapers/output | /usr/bin/sort -R | /usr/bin/head -1 )

/usr/bin/${GCONF} write /org/mate/desktop/background/picture-filename \
  "'/home/crobin/Pictures/Wallpapers/result/${RANDOM_WALLPAPER}'"