Exactly, @shaynewhite! This is one of iTunes' best "secret" features, and now it's gone from the new Music app.
*Displaying "Fit to Screen" full-size album artwork*
How to enable this feature on *iTunes*: Command-Click (while holding the Command button, click) on the tiny album artwork square up in the iTunes header. This pops up the album artwork medium-large and center on your screen. Then, right-click that, and choose "Fit to Screen". Myself, I then drag this huge artwork window to become the right-hand half of my iMac's screen, while the iTunes program main display occupies the left half of my iMac's screen. The album artwork updates as you play different albums & artists, which really adds to the iTunes experience. (Why is Tim Cook not showing people that they can do THIS on their beautiful widescreen iMacs? That would sell it for me! Is looking at tiny artwork & bloated amounts of white space really more appealing?)
I will miss this terribly if it is gone forever from the new Music app. :-(
Does anyone know How to do this in the new Music app?