A quick Google search revealed little biographical information about him, though this site is fairly useful.
Besides working in many media, Horter used a variety of styles over the years, as can be seen in the images below. So even though he was very competent, his work is not distinctly "his" due to all that variety. That said, it should be noted that his subject matter was largely architectural or townscapes. Almost no images featuring people could be found on the Internet.