Nice script, but one thing is there is a sleep process that you can't easily turn off as a result of the timer part. And, also, if you run it manually more than once, more than one sleep process that you can't turn off occurs.

Anyway, not to condone this script, as it does work just fine, here are a couple I prefer. And they handle spaces in paths and such.

###### Random wallpaper (add whatever wallpaper directory(s) you wish after 'BACKGROUND_DIRS')
#!/usr/bin/env python
BACKGROUND_DIRS = ['/usr/share/backgrounds', '~/Pictures/Backgrounds']
EXTENSIONS = ['jpeg', 'jpg', 'bmp', 'png', 'svg']
import os, glob, random, itertools, gconf
files = list(itertools.chain(*[[os.path.join(dirpath, name)
for name in filenames]
for dirpath, dirnames, filenames in
itertools.chain(*[os.walk(os.path.expanduser(d))
for d in BACKGROUND_DIRS])]))
gconf.client_get_default().set_string(
'/desktop/gnome/background/picture_filename',
random.choice(files))


###### Automatic wallpaper switcher for Gnome
#!/bin/bash
if [ $# -ne 2 ];then
echo -n "Usage: $0 directory_name timeout_in_seconds
Leave the directory name blank for Current Directory
For you lazy pal, I assume timeout as 5 sec and Directory as current
Do you want to accept this settings? (Y/n): ";
read response
if [[ "$response" =~ ^[^yY] ]];then
exit 0
fi
fi
function set_wallpaper() {
gconftool-2 -s /desktop/gnome/background/picture_options "centered" -t string;
gconftool-2 -s /desktop/gnome/background/picture_filename "$1" -t string;
}
TIMEOUT=${2-5};
WALL_DIR=${1-`pwd`};
echo "Timeout value is: $TIMEOUT";
echo "Directory is: $WALL_DIR";
echo
if [ ! -d "$WALL_DIR" ];then
echo "The Directory Specified is invalid..";
exit 1;
fi
filelst="$(find "$WALL_DIR" -type f -name '*.jpg' -o -name '*.png')";
if [ -z "$filelst" ];then
echo "No Suitable files found in this location: $WALL_DIR";
exit 1;
fi
while true;do
filename=`echo "$filelst" | shuf -n 1`
set_wallpaper "$filename";
sleep $TIMEOUT;
done
exit

That's right. Perhaps I will fix it next time.
Thanks.

Ah. Yeah, it became quite annoying that every time I tried to kill the 'sleep' processes they just kept returning. I had to restart just to get rid of them. hehe