Ever wanted to have wallpaper downloaded from Flickr directly using the tags and then apply them as wallpaper, then the way to go is download Webilder here. Just do the regular stuff to install the same.
tar xvfz <filename>
cd <to the directory created>
sudo make install
And then right click on the gnome panel and add the widget. Configure the tags to download and the duration to change the wallpaper and enjoy.