Others may disagree or had ok experiences but I would never hang a mirror or glazed picture with Command Strips.
In my old house, they were fine and had no problem hanging various things like mops, apron, quilting rulers etc - never pictures or mirrors. When I moved I used them to hang up these same fairly lightweight things in my workroom and utility area. Within 6 months every darned one had come off the wall. Luckily nothing broke.
A friend hung up a glass wreath she made with one, within a few months it came off the wall and smashed.
The strips are only as good as the adhesion of the paint to the plaster.
HettyB