ok, so what exactly are they violating? If it's a free app?
If it's a violation, then I guess google chrome, safari, and firefox are all guilty too, along with every other web browser made.
If you can browse to the photos on the internet, then the application that is doing it makes no difference.
I download wallpaper, youtube, and many other media formats all the time. If you can get to it legally, it's fair game for personal use. It doesn't matter what web browser or application you use.
With that said, it still looks fishy. It doesn't seem to be working right now, and MU has it marked as free, so why is there a license code?