OK, lousy pics, but they kinda work, and are the best I can do right now.
First, just the glass. You can see the line on it - this delineates the spot where the glass becomes convex.

Next, with my old mirror. Obviously, the stick-on convex mirror shows more, but it also takes up a quarter of the viewing area. It's also too small to be of any real use except at night, when you can see headlights in it.

Last, a view through the window, FWIW.

It's not a HUGE difference, but it is definitely an improvement over stock. Plus, being heated makes them especially useful in the winter. I wired them in to the defroster circuit, so when I turn on my rear window defroster, it turns on the mirror heaters.