If you would like to use images as wallpaper simply place them in you pictures directory in your home folder or create a folder called wallpaper in it and place all your images there. then right click for desktop settings and in the folder drop down choose other and navigate to your folder of images then click open. your folder of images will appear in the selection window replacing the default and you can select the one you like.
If you want the default you can choose other and navigate to/usr/share/backgrounds and select it. you will notice that opening that folder gives you all the images in the directory including the xfce folder inside the backgrounds folder. although I do not really know, I suspect to offer the single image as a default a link was created to establish that ..perhaps this allows the system to generate a single wallpaper for the user...get the idea..logic is relative....could be that the tree includes a folder called backgrounds and xfce uses the backdrops folder or a link in it to point to the xfce wallpapers folder in /usr/share/backgrounds..so to customize a link was placed in /usr/share/xfce/backdrops pointing to the image in /usr/share/ backgrounds..not for me to question why as much as how to work around it. perhaps not the actual answer you were looking for,sorry.. if you really NEED to know post the question to the majaro forums perhaps.
p.s. if you want the default single image back then navigate to /usr/share/xfce/backdrops and open and the single image will appear in the selection window.
hope that helps
Last edited by dadadio; 07-13-2014 at 03:25 AM.