This photo was taken, as the title says, in 1853. It shows William Henry Fox Talbot's studio in action. Left to right, we see a photographer exposing a negative to copy an artwork. Behind the artwork, we see someone emerging from the darkroom, tilted as if caught in mid stride. In front and to the right of the darkroom technician, we see a subject sitting for a portrait. The photographer of that subject, at the far right of the image, is caught in the act of removing or replacing the lens cover.
Note that the portrait subject's head is drooping, as if he's asleep. It's not clear in this image, but behind him we can see the back brace necessary to hold still for the long exposure necessary (still several minutes at that time).
But when we realize that this is itself a photograph, we also realize that a subtle joke has been played on us. The two photographers and the technician all must be braced for stillness; they're as sharp as the gravel at their feet. The posture of the two photographers especially shows they're braced for a long exposure. These aren't the stances of someone working, someone who has to finish one task and move efficiently on to the next. If he weren't posing, the photographer on the right would be very unlikely to straddle the leg of the tripod the way he has. Even a slight jiggle in a long exposure can cause blur. Sometimes I think I see a smirk on his face, as if he can barely restrain himself from laughing.