Hi Tosick,
I often use photos that I have taken as backgrounds, and instead of moving one picture at a time to /usr/share/backgrounds or in ~/images/wallpapers, I have created a symbolic link to my photos directory in /usr/share/backgrounds. Since I'm the only user on this computer, it doesn't matter if the link is in /usr/share/backgrounds or in ~/images/wallpapers. So here's what I did:
sudo ln -s /mnt/data/photos/ /usr/share/backgrounds/
Note that since my Archlinux crash, I keep all my files in a separate ntfs partition that I call data, and only keep configuration file in my home directory. So in your case, just replace /mnt/data/photos/ by the directory you use to store your photos.
Alternatively, you can create a symbolic link to your photos and put it in ~/images/wallpapers as:
ln -s /path/to/your/photos/ ~/images/wallpapers
sudo is not necessary here for ~/images/wallpapers. In this case, other users would not have access to your photos as backgrounds.
Hope this helps,
Ghoti 
Many of life's failures are people who did not realize how close they were to success when they gave up.
Our greatest weakness lies in giving up. The most certain way to succeed is always to try just one more time.
Thomas A. Edison