How do I add album art to music on my Samsung Galaxy J5 (2016)?
Some media players will download it if your phone is connected to the Internet and automatically load it, others won't. To avoid this across the board, when ripping music on my computer, I use MP3Tag to apply album art to all tracks for albums that may not have it for whatever reason. That way no matter what media player I use, or file type (MP3, and specifically FLAC) will have the album art regardless or the media player (as long as the media player can display Album Art).