Why am I unable to change opacity of background images in Blender 2.82 (sub 7)? Current animation student, need to learn everything about latest Blender engine. Using Pluralsight to supplement on-ground college courses. Current module requests opacity change of background reference image. Unable to comply. Blender v2.82.7 has the opacity under image grayed out so that when turned up or down, does not affect the image.

Hoping someone has a remedy for this, really seems like a simple command, can't believe it's this frustratingly hard to create this effect, should be a staple in modeling.
In order to change the opacity level you have to turn on Use Alpha. In your screenshot it's the third field from the top.