Amgad Abdel Ghaffar, head of the State Information Service, the government's media arm, had already apologised for the poster, which featured Caucasian-looking images under the caption: "All Egyptians Constitution."
State television said he had tendered his resignation.
The large poster, featuring a doctor, a woman, a peasant and a soldier, was meant to capture a cross-section of Egyptian society.
But at least three of the images turned out to be of non-Egyptian models featured in stock photographs on other websites.
The banner also misspelled "Egyptians" in Arabic, as pointed out by one journalist at the press conference held earlier this week to promote the constitution ahead of a referendum in January.
Egypt's military-installed government has billed the referendum as a key step in a democratic transition following the army's overthrow of Islamist president Mohamed Morsi in July.