Meanwhile, a young female soldier at the heart of the abuse probe tells a CBS station said she was "instructed by persons in higher rank" to pose for the pictures.
The photographs were being made available for three hours Wednesday afternoon in a high-security, classified office in the Capitol. After that, they were to be returned to the Defense Department while the U.S. administration decides whether to make them public.
Fears that the prisoner abuses would trigger a violent backlash appeared to be realized Tuesday when a video was posted on an al Qaeda linked Web site showing the . The video said the killing was to avenge the prisoner abuse.
Meanwhile, the U.S. military has into allegations that an Afghan police officer was stripped naked, beaten and photographed at a U.S. base in Afghanistan.
CBS News' 60 Minutes II has obtained an American soldier's in Southern Iraq and Abu Ghraib in Baghdad, where American soldiers have been accused of abusing Iraqi prisoners.
The video shows a young soldier's disdain for the Iraqi prisoners. She says: "We've already had two prisoners die … but who cares? That's two less for me to worry about."
The viewing of pictures in the Capitol comes a day after senators challenged military officials who pinned most of the blame for the mistreatment on a small group of soldiers and on supervisors who provided inadequate training and leadership.
The Army officer who investigated the abuses, Maj. Gen. Antonio Taguba, told the Senate Armed Services Committee that military police who acted improperly did so "of their own volition."
But several senators questioned whether low-ranking soldiers would have created the sexually humiliating scenarios by themselves.
"It implies too much knowledge of what would be particularly humiliating to these Muslim prisoners," said Sen. Susan Collins, R-Maine. "And that is why, even though I do not yet have the evidence, I cannot help but suspect that others were involved, that military intelligence personnel were involved, or people further up the chain of command."
Sen. Ben Nelson, D-Neb., challenged Taguba on his statement that Brig. Gen. Janis Karpinski, who headed the 800th Military Police Brigade at the prison, bore responsibility for a breakdown in discipline that led to abuse.
Taguba testified that orders were issued taking tactical control of the Abu Ghraib facility away from Karpinski and given to Col. Thomas M. Pappas, commander of the 205th Military Intelligence Brigade.
Taguba said the order placing Pappas in charge of prison policy where Karpinski's MPs worked created a confusing situation and was contrary to Army doctrine. Nonetheless, he found that Karpinski retained overall responsibility for the MPs in her brigade and assigned much of the blame for the abuse to inadequate leadership on her part.
Asked to put in simple words how the abuses happened, Taguba said: "Failure in leadership, sir, from the brigade commander on down. Lack of discipline, no training whatsoever and no supervision. Supervisory omission was rampant."
Karpinski has been suspended and issued an official letter of admonishment in connection with the abuse. She has not been charged and has asserted other officers are attempting to make her a scapegoat.
Taguba also said that the guards at Abu Ghraib "were directed to change facility procedures to 'set the conditions' for (military intelligence) interrogations."
However, he did not conclude that the abuses were part of an official policy.
"I think it was a matter of soldiers with their interaction with military intelligence personnel who they perceive to be competent authority who were influencing their action to set the conditions for interrogations," he said.
Taguba and Stephen Cambone, the undersecretary of defense for intelligence, disagreed over whether it was appropriate for MPs to "set the conditions" for interrogations. Last fall Maj. Gen. Geoffrey Miller studied U.S. prisons in Iraq and said suggested that military police guards in Iraq "set the conditions for the successful interrogation and exploitation of internees and detainees."
Cambone said Miller, who has now taken over the Abu Ghraib jail, was merely "underscoring the need for military police and military intelligence personnel to act in a fashion such that the one did not undermine the efforts of the other."
In an interview with reporter Brian Maass of Denver CBS station KCNC, Army Pvt. Lynndie England, a 21-year-old who is four months pregnant and features in some of the abuse pictures, blames the abuse on order from superior officers.
"I didn't really, I mean, want to be in any pictures," England said. "I was instructed by persons in higher rank to stand there and hold this leash and look at the camera. And they took a picture for psy-op (psychological warfare operations). And that's all I know."
"They'd come back and they'd look at the pictures, and they'd state, 'Oh, that's a good tactic, keep it up. That's working. This is working. Keep doing it. It's getting what we need.'"
The material senators were reviewing Wednesday was expected to show abuses that go well beyond the sexual humiliation depicted in photos already circulating publicly.
Sen. Lindsey Graham, R-S.C., told reporters last week, "The American public needs to understand we're talking about rape and murder." Defense Secretary Donald H. Rumsfeld said of the photos and videos: "If these are released to the public, obviously it's going to make matters worse."
Some lawmakers have urged President Bush's administration to release all the photos at once. They say that would be less damaging than seeing the photos gradually surface in the media a few at a time over weeks or months. Administration officials say they are worried that releasing more photos could derail criminal prosecutions for the abuse.