Did you make the edit in Valence or someone else? Just wondering when this was done.
Does your screenshot contain the whole of the vertical size of the picture and is your Roon fullscreen? The image size in your screenshot looks vertically very narrow to me.
It looks fine here, MacBook Air, showing the whole Roon window in fullscreen:
Well, @Suedkiez 's post prompted me to look at my Mac’s screen settings. So it clicked the green full screen button once, which shrunk the page, then clicked it again, and voila: