I frequently see a big empty space at the bottom right in Longplay (Mac), as I have a high resolution monitor, and maybe a smaller than average collection.

I think a tessellated grid of squares the same size as the album covers would look much nicer as a background than just an empty white box, could easily be randomly generated from either grayscale tones, or from a selection of album cover colours.

You could even detect and adapt to the system colour scheme or light or dark.