Wallpaper - doesn't work like it used to

Wallpaper - what happened to taking a picture on the desktop, dragging it into the black window at the top of the wallpaper page and then choosing Fit to Screen for pictures in Portrait Mode so that the picture shows on the desktop with color bars on either side rather than filling out the entire screen and losing a lot of the original pictures in the process? As it stands, I don't think the black rectangle in Wallpaper, even accepts a picture dragged on it. You used to be able to do this but it seems, not now. Control clicking on a photo now just plasters the picture across the entire desktop which is fine for a Landscape picture but not for a Portrait picture. So any surefire way of ensuring that a Portrait Mode picture is displayed properly on the desktop (mine is a Studio Display) with color bars?