This girl is stealing other people's horse photos and posting them for people to download as desktop wallpaper. She stole 14 of my photos, and I know for a fact that some of her other photos are stolen because I know the people who took them. I highly recommend reporting your photos if she has stolen any. She has hundreds of stolen photos and she keeps uploading new ones each day.
All you have to do is click on "Report This Wallpaper" underneath the picture and fill out your email address. When you get the email, copy the link they give you and fill out the form there. It usually only takes a few minutes for the photo to be deleted from the site. I'm really annoyed that I had to fill out that form 14 times, but what she's doing is wrong and illegal.
Here are her uploads:
Uploaded Wallpapers by spanish_girl - My Desktop Nexus
You're only allowed to fill out a copyright claim if you own the rights to the photo, but you can tell the owner of the photo about it. That's how I found out, and I'm really glad they told me.