[dgourd]

That is actually the background on Windows Today screen, not TouchFlo. While TouchFLo is loading, you are shown the Windows Today screen which has nothing on it, just the background.

Go into the settings tab -> All Settings -> Personnel -> Today and you can change the background.

The easy way is to find a picture in your file explorer and tap and hold it. Then press set as Wallpaper. This sets the wallpaper for the today screen instead of TouchFlo.

If you want awesome wallpapers for touch flo check out the thread linked in my signature.