Lieberman, Ind-Conn., and Collins, R-Maine, said they would defer to President Barack Obama's judgment on whether to release the photos, but said they would prefer the photos or some other evidence be released, Politico reported.
Both are senior members of the Senate Homeland Security Committee.
Earlier, Obama's counter-terrorism adviser, John Brennan, told reporters the White House would decide later on whether any pictures should be released.
Politico reported Lieberman said, "Unless there's an acknowledgment by people in al-Qaida that bin Laden is dead, then it may be necessary to release the pictures -- as gruesome as they inevitably will be because he's been shot in the head -- to quell any doubts that this somehow is a ruse that the American government has carried out. So my own instinct is it's necessary to release those pictures, but I will respect whatever decision the president makes."
Lieberman and Collins said they personally have no doubts bin Laden was killed Sunday.