Library display problems

Hi
New user to Volume. Running a Raspberry Pi using local files on a hard drive.
Problem is, in the app the library is not as it should; many photos wrong or missing, compilations/mixes split into single tracks.

Is there anyway of re-arranging my library as it should be? How can I change artist/album artwork?

TIA

Use tag editing software, such as MP3Tag to ensure all the music is tagged correctly and consistently.
Add folder.jpg (other names and file types can also work, see the documentation) with the album cover to each album folder.