Front and Rear Cover Art

Is there a setting to view both the front and rear cover art on the main window at the same time. I have added the back cover art to almost all my collection

First, at the risk of stating the obvious: if you hover your mouse over the front cover, a “flip” icon will appear, that lets you flip to the back cover.

But I suspect you are suggesting to make the back cover visible next to the front cover? Yes, that is something we are thinking about for the upcoming re-design of that details area. Maybe we’ll make it adaptive, so that the back cover appears only when there is enough room and auto-hides on smaller screens.