Isn't this a photo of Joseph?

The man in the photo above is Alexander Hugh Holmes Stuart, and there are several reasons why we know that. First, the plate has the surname "Stuart" scratched into the bottom right corner.

The Library of Congress has this daguerreotype identified as Alexander Hugh Holmes Stuart.

The same image is used on a Wikipedia article about him.

Two other images of Alexander H. H. Stuart confirm that he is the man pictured above.

There is substantial evidence that the man pictured is Alexander Stuart, and there is no evidence or reason to believe that he is Joseph Smith beyond wishful thinking.