Album Artwork not syncing to iPhone

Currently running the most recent version of iOS and I am on Mac OSX BigSur. I try to sync a new album to my phone and it carries over everything except for the album art.

Things that I have tried:

1. Removing all music and then syncing it again
2. Restoring my phone from an old backup and then syncing them
3. Made sure that the album art is attached to every song on the album.

I'm at my wits end.

Solution 1:

So I don't know if this is the exact reason or not, but it seems to have solved my issues. I think my problem was that the album art was slightly to high of a resolution.

I scan my own album art when it isn't in a database or available online, and it turns out that 600dpi gives you images with about 600x600 pixels per inch. I lowered my scans to 300dpi and haven't had an issue since.