Not sure of all the file formats, but it can play mp3, .txt files .jpg not sure about the video format, it also can play .nds (roms.) If you check the R4 website you can find out all the other extras it can do, it doesn't disappoint.
installing skins on the R4 is simple, there is a folder called themes on the R4 (I think there are about 12 themes that come with the R4)just paste your new theme into one of the folders replacing the old ones. http://www.ndsthemes.com have some good themes for the R4 and M3 downloadable for free.
on the website you gave me, there were themes for m3,r4, and moonshell. i know moonshell is like the program used to watch videos, music, ect. but how do u change the skin for moonshell?
