I looked all over for a date and got everything from “early 1800s” to “late 1800s” but nothing exact, so I had to make an educated guess. The first cameras practical enough to take such a photo were developed around 1840 and the excavations began in 1867.
Damn, this really puts into perspective for me that the sphinx was once in the center of a thriving and powerful civilization that completely died. All of that sand accumulated over thousands of years wiping out every trace of the world that used to be there and we only have evidence for it in the handful of mega structures they managed to build in an ocean of nature identical to any other undeveloped part of earth.