The picture showed a yellow can of Schweppes Gold, a flavored soda marketed in Egypt, and what appeared to be other bomb components made of plastic and metal. The group also published a picture of what it said were passports belonging to people who died in the plane crash.
The photos could not be independently verified.
The extremist group, which has a powerful affiliate in the Sinai, had previously claimed to have downed the plane, which was mainly carrying Russian tourists, without offering further details. It said the attack was to avenge Russia's air campaign against the group in Syria.
The group said it "discovered a way to compromise the security at the Sharm el-Sheikh International Airport," without providing further details. It said it initially planned to bring down a plane from one of the countries participating in the U.S.-led coalition that has been striking it in Syria and Iraq. But it says it changed the target to a Russian plane after Moscow began launching airstrikes in Syria in September.
Russia's FSB security service said Tuesday that a bomb brought down the plane, after Western officials had earlier expressed similar suspicions. Egyptian authorities have declined to comment on what caused the Oct. 31 crash, saying a multi-national investigation is still underway.
Bob Ayers, a former CIA officer and an international security analyst, said it would be "easy" to bring down a commercial airliner with a device hidden inside a soda can like the one the Islamic State group says it used against the Metrojet flight.
"To bring down an airplane, you don't need to blow it apart, you just need enough to rupture the pressure hull of the aircraft and the air pressure will do the work for you," he said.
He said a can with a device inside could "blow a really nice hole" in an airplane and was in some ways an ideal size for an attack.
Ayers said there would be little in the way of detection devices that could prevent such a device from being brought onto a plane in cases where a member of the ground crew was willing to take a bribe.
Suspicions that a bomb caused the crash have led to flight cancellations to and from Egypt and dealt a major blow to its vital tourism industry.
The U.K. banned flights to Sharm el-Sheikh on Nov. 4. Russia banned all flights to Egypt a day later, and last Friday it banned Egypt's national carrier from flying to Russia.
Earlier Wednesday, Egyptian President Abdel-Fattah el-Sissi told Russian President Vladimir Putin that Egypt understands the Russian people's pain. Egypt's presidential spokesman Alaa Yousef confirmed the two leaders spoke by phone Wednesday in a statement that made no mention of a bombing.