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.
Fun fact: Shelley wrote that poem in a friendly competition with Horace Smith. Here is Smith’s version:
In Egypt’s sandy silence, all alone,
Stands a gigantic Leg, which far off throws
The only shadow that the Desert knows:—
“I am great OZYMANDIAS,” saith the stone,
“The King of Kings; this mighty City shows
The wonders of my hand.”— The City’s gone,—
Naught but the Leg remaining to disclose
The site of this forgotten Babylon.
We wonder — and some Hunter may express
Wonder like ours, when thro’ the wilderness
Where London stood, holding the Wolf in chace,
He meets some fragment huge, and stops to guess
What powerful but unrecorded race
Once dwelt in that annihilated place.
— Horace Smith, “Ozymandias”
That is beautiful as well!
I kinda like it better since it makes the same criticism of people who think their works will last forever, but then goes a step further and exposes the same fallacy in modern peoples.