Album art not updating
Just on a remote possibility there's something wrong with the card's file system -- micro SD cards have FAT32 as their default file system, the issue being FAT32 is dated and wasn't the most reliable, robust file system even back in its day.
It's support for modern day file metadata and file/folder permissions is only border-line stable at this point anyway.
It has never been separated out into a folder of its own (that is unless the player happens to build one behind the scenes, but if it does the album art should still exist in the source folders for doing so).Apps menu and open up the entry for the Samsung Music app, if you scroll down to 'App details', open it and there should be some reference to 'Last updated...' Was there any update to the app around the time when it stopped showing your album art?It says last updated on July 17 2018 so that can't be the problem, since I have this phone since October.Still I prefer the default Music app although I have now switched to foobar2000 due to this problem.If you use Windows Media Player 12 in Windows 7, you may notice some of your media is missing information when displayed in the library.
On the Find album information window, click Edit under Existing Information.