I figured out the issue. Glider cannot pull the album art out of hi res files. If I use Hi Res AIFF, it displays the metadata but no album art. If I use Hi Res Wav no metadata appears at all.
Strangely, if I use a redbook copy of the same track, all metadata including album art shows up and the Hi Res file show the album art too. However, this will require a standard 44.1 double of every file.