Hello everyone!
It’s been a long time since I posted here the last time. After talking on the IRC channel, RetroArch authors were concerned about possible problems since game boxarts are intellectual property, although I am always using a lo-fi version (the thumb instead of the big image) and this is allowed by the fair use policy.
So I decided to make my app stand-alone, to avoid problems to RetroArch, and give it a totally different look. The app is called Gamesome Frontend and it’s on the play store for free. The other big difference is that the GUI doesn’t support only RetroArch, but even some other main emulators. So that it really is a universal emulation frontend.
Source code for this gui will remain on github for anyone interested in continuing/improving my work.
Thanks to anyone who gave his/her feedback in this topic!