Don't underestimate the capabilities of our ancestors in photography. I don't know where, but I think I read somewhere that they were even capable of printing life size figure photos (so up to 2 meters high) in the 19th century. For printing, a solar enlarger could be used, using the sun as the light source.

Also, camera's as big as your print, are known from these days.

As for printing techniques capable of photo rendition, there were a couple of processes, like Woodbury-type. But these use more or less stable printing inks, related to oil paints, and shouldn't show the same image degradation silver based processes can show. Looking at the image with a loupe might tell something, together with inspecting the sides of the image. Some printing process like Woodbury, left clear signs of their origin along the borders of the image.