Astro Boy Tap Tap Rush sprites

[Garamonde]

Well, it's more or less like any ROM in that regard. If Panda Apps doesn't work then try to Google the game instead.
Yes some of them do use weird formats, like all platforms, but many of them don't. The reason why they're the easiest is because you only have to open up the game and extract what's inside.
Otherwise, you're okay downloading them, especially if you're just ripping stuff from it.
There are however mobile phone emulators out there somewhere if you want to play the game to get to know about it before you submit stuff.