The extremely graphic photographs of the dead brothers were distributed on CD-ROM in Baghdad, where many news wire services have reporters stationed. The pictures later were distributed to other news outlets.
The U.S. military hopes the photographs will convince fearful Iraqis that Uday and Qusay died in Tuesday's raid on a house in the northern city of Mosul.
Two of the photos show Uday, the older brother, with a thick beard and a severely bruised and bloodied face. He has a gash running from his left eye to the right corner of his mouth, and there are bruises over his forehead.
Qusay, depicted in two other photos, has bruises and blood marks on his eyes, and a beard. His mouth is open, his teeth are showing, and his face is far more intact than Uday's.
The pictures show the men from the chest up -- one on bloody white sheets and the other in what appears to be a body bag. The faces are caked with blood, the eyes are closed and the lids are darkly bruised. The brothers had never worn such thick beards, and may have been trying to disguise their identities as they spent three months in hiding from coalition forces.
For comparison, U.S. officials also released photos of the brothers when they were alive, as well as X-rays of Uday -- who was wounded in the leg in an assassination attempt in the 1990s.
Senior defense officials told Fox News that the bodies were not repositioned in any way and that the pictures were not altered. U.S. officials are still awaiting official autopsy results.
"The careers of the two of the regime's ... henchmen came to an end," President Bush said in Philadelphia after the pictures were released. "Now, more than ever, the Iraqis can know that the former regime is gone and is not coming back."
Secretary of Defense Donald H. Rumsfeld (search), asked at a Pentagon news conference why the extremely graphic pictures had been released, said: "This is an unusual situation. This regime has been in power for decades. These two individuals were particularly vicious individuals. ... They are now dead. ... The Iraqi people have been waiting for confirmation of that and they in my view deserve having confirmation of that."
Rumsfeld added: "It was not a close call for me."
L. Paul Bremer (search), the U.S. administrator of Iraq, said he "would not be surprised to see an uptick in violence against our forces" following the release of the photos. But he said the deaths of Uday and Qusay will ultimately "help reduce the security threat to our forces."
In the long run, Brenner emphasized, their deaths will likely encourage Iraqis to give authorities tips about other at-large members of the Baath Party (search).
Arab satellite station Al Jazeera and Al-Arabiya were showing the pictures over and over in Iraq and the Arab world, while celebratory gunfire was going off in Iraq.
The Iraqi Media Network (search), established by the U.S.-led coalition, may also broadcast the pictures, and Iraq's U.S.-backed newspaper will include them in a special edition.
Coalition aircraft also may drop leaflets containing the photographs so that all Iraqis get the word that Saddam's sons are dead.
Defense officials earlier said it was possible that Uday committed suicide, but a senior defense official said later that there simply isn't enough evidence in the photos to determine that.
Both bodies have visible shrapnel wounds. While suicide is a possibility, officials said they will wait for autopsy results before making any conclusions.
In Baghdad, some members of Iraq's Governing Council were shown the brothers' bodies, which are being kept at Baghdad International Airport, said a spokesman for the Coalition Provisional Authority (search).
The authority also was talking with council members about how to release pictures of the bodies to the public.
"There isn't the slightest doubt in our minds that these are the bodies of Uday and Qusay," the spokesman said.
The military released the photographs to convince skeptical Iraqis that the feared brothers were dead. Many Iraqis, especially Saddam supporters, believe the story of the brothers' deaths was concocted by the American military to demoralize opponents of their occupation of the country.
The Coalition Provisional Authority and Secretary of Defense made the decision to release the photos, White House spokesman Scott McClellan said Thursday. Bush was fully informed of the decision. Pentagon officials hope that releasing the pictures will reduce the number of attacks against U.S. forces in Iraq.
Fox News foreign affairs analyst Dennis Ross said showing the pictures to Iraqis -- and the world -- is critical if the coalition wants to eliminate some of the fear the Iraqi people have been living in.
"What we have to do is prove what we were saying, especially on an issue like this," Ross said. "Psychologically, it's critical and just in terms of our own credibility, it's required."
Dr. Michael Baden, a forensic pathologist, said that showing pictures of dead bodies is "very inflammatory," and more scientific evidence will need to be publicized to persuade those who believe they may simply be body doubles.
"Showing thumbprints may be less inflammatory and more scientific ... you can't fake fingerprints. Even James Bond can't fake that," Baden told Fox News.
"I think right now this is a temporary measure" until DNA, fingerprints, dental records and other evidence can be released, he said.
Retired military intelligence officer Timothy Lomperis told Fox News that it's very unusual for the U.S. military to show pictures like this, but it's obviously a much-needed move in this situation.
"It's a powerful symbol of the end of a brutal regime," Lomperis said. "I think the most powerful will be the capture of Saddam himself."
U.S. officials have always hoped that as more regime members are caught, more Iraqis will come forward with information as to where the others -- most importantly, Saddam himself -- are hiding.
And the day Saddam is caught or killed could be near, experts say.
"I think it should lead us very soon to the father; the father can't be far away from the sons," Lomperis said. "I think it's a matter of just days before the regime in its entirety is gone."
Uday and Qusay were killed Tuesday when 200 U.S. troops stormed a house in Mosul where they were staying.
After coming under fire during repeated attempts to enter the building, troops attacked with helicopters, grenades, heavy machine guns and anti-tank missiles. It's believed that heavy tow missiles actually caused the sons' deaths.
For Uday, dental records matched 90 percent -- a 100 percent match could not be made because of injuries sustained in Tuesday's attack. The dental match for Qusay was 100 percent, the U.S. military said.
"Autopsies will follow, but we have no doubt we have the bodies of Uday and Qusay," Lt. Gen. Ricardo Sanchez said. "The Saddam Hussein regime will never come back to power."
Four formerly high-ranking Iraqi officials in coalition custody were shown the bodies for a positive ID. One of those was former Deputy Prime Minister Tariq Aziz.
Another was Abid Hamid Mahmud Al-Tikriti, Saddam's top aide who surrendered June 17 and was the ace of diamonds in the U.S. military's 55-most-wanted deck of cards.
Only 18 of the original 55 most-wanted are still at large. Uday and Qusay were Nos. 2 and 3 on the list.
Fox News' Bret Baier and Greg Palkot and The Associated Press contributed to this report.