It's not an autoharp: as Desert Dancer has pointed out, there are no chord bars and too few strings. It looks more like some kind of psaltery, but the wrist strap, small number of strings. one-handed playing and vertical position suggest some kind of lyre. The picture may be late 19thC, but it's mock-mediaeval. One has to be careful with iconography where musical instruments are concerned. Sometimes artists depict actual instruments accurately, but they can also depict things which never actually existed outside of their own imagination.