How to get the picture of the earth back on iPhone 4?

I changed my moms lock screen picture on her phone and previously she had the picture of the earth, how do I get that back?

There are some suggestions in this thread:

extract photos from iphone backup files?

particularly this one:
iPhone / iPod Touch Backup Extractor

But all of them require you to have "good" backups with the pictures somewhere on the computer you used to sync the phone with.

Unfortunately, you can't run the kind of low-level "rescue" software on the iPhone the way you have on SD cards. The filesystem doesn't work that way. There aren't any JB programs that will do it, because they all work *within* the iOS storage API, and not around it.

Unfortunately, they have taken off the Earth wallpaper from their selection. But, you can still get it back. If you open up your Safari browser on your iPhone, go to Google, and then images, then type "iPhone Earth", the picture is there. (The first one). Click on it. Then go to view full size image. A lot of people don't know this but, if you hold down the picture, you can save it to your Photo Album. Do this, then open your Photo Album, click on the picture, then on the bottom left corner, it gives you options for this picture. Click on it, then click "Set as Wallpaper", and there you go.