In an interview with Fox News, Saudi Foreign Minister Adel al-Jubeir referred to Khashoggi's reported death as "murder" for the first time.
The images, which were published by CNN on Monday, show the decoy leaving the Saudi consulate in Istanbul by the back door, wearing Mr Khashoggi's clothes, a fake beard, and glasses, in the hours after he was killed.
Saudi officials have offered inconsistent narratives of how he was killed and have so far refused to answer questions about where Khashoggi's remains are, prompting a global uproar over the Saudi writer's death.
Saudi authorities acknowledged on Saturday that Khashoggi was killed October 2 at the consulate under still-disputed circumstances.
The claim the Saudi journalist was killed in a fight was shrugged off by Turkish President Recep Tayyip Erdogan's government.
Saudi Arabia has sought to check the fallout by arresting 18 people suspected of killing Khashoggi, dismissing two top officials and claiming the journalist and government critic died accidentally after being put in a chokehold.
Before Riyadh's admission, Turkish sources said a team of 15 Saudis were sent to Istanbul and killed Khashoggi, a critic of the crown prince who moved to the United States a year ago and wrote for the Washington Post.
The newspaper says the calls went to the head of the crown prince's office, as well as a number in the United States.
Britain joined forces with France and Germany yesterday with a joint statement condemning the killing of journalists as unacceptable.
Not only did they ostensibly bring in a body double, but according to this report, it appears they also dressed him in Khashoggi's very clothes in an attempt to mislead those looking into his disappearance.
"The world is watching", Kushner said was his advice to Prince Mohammed.
Turkey's Anadolu agency said early on Monday that Erdogan and Trump had spoken on the telephone and agreed that "all aspects" of the case needed to be cleared up.
The next day a Saudi official insisted that Khashoggi had left shortly after getting the paperwork and that he was "not in the consulate nor in Saudi custody".
Five Turkish employees of the Saudi Consulate said in their testimonies that they weren't given a day off on October 2 and left the consulate when their shift ended at 3.30 p.m. local time (1230GMT). We are determined to find out all the facts.
However, a leading U.S. Senate Republican said the Saudi explanation, which followed initial denials from the kingdom that it knew anything about Khashoggi's fate, wasn't credible.
He told journalist he knew Saudi Consul General Mohammad al-Otaibi, who left Turkey for Riyadh last week.
The Saudi kingdom also has the death penalty for homosexuality, among other human rights outrages.