Fixed it so that it actually works.

Desktop/randomWallpaper.sh

@@ -5,24 +5,28 @@
 
 # Public Domain or CC0
 
-function setGnomeGConf() {
-	gconftool -t str -s /desktop/gnome/background/picture_filename $1
+setGnomeGConf() {
+	gconftool -t str -s /desktop/gnome/background/picture_filename "$1"
 }
 
-function setMateConf() {
-	mateconftool-2 -t str -s /desktop/mate/background/picture_filename $1
+setMateConf() {
+	mateconftool-2 -t str -s /desktop/mate/background/picture_filename "$1"
 }
 
-function setMateDConf() {
-	dconf write /org/mate/desktop/background/picture-filename $1
+setMateDConf() {
+	dconf write /org/mate/desktop/background/picture-filename "'$1'"
 }
 
 # Directory of the wallpapers
 wallpaperdir=~/Wallpapers
+
+# Time between changes
 sleep=3m
 
+
 if [ ! -d "$wallpaperdir" ]; then
 	echo "$wallpaperdir does not exist!"
+	exit 1
 fi
 
 newWallpaper=$(ls "$wallpaperdir" | sort --random-sort | head -n 1)
@@ -32,4 +36,4 @@ setMateDConf "$wallpaperdir/$newWallpaper"
 # Wait for some time and then start over.
 # If you want a "one shot solution" remove the next two lines.
 sleep $sleep
-exec $0
+exec "$0"