If you stacked them in your living room they'd fill every inch of space right up to the ceiling. And the dining room too. With maybe a knee-high pile left over in the hall.

The National Archives has acquired 6,600 fat albums of military photographs from the Army: some 500,000 negatives and 2 million prints dating from 1940 to 1954. They cover the Army'srole in World War II and Korea, and this trove is now available to the public.

No living person knows exactly what's in the immense collection. The 8-by-10 glossies are cross-filed various ways, by unit, area, event, personality and so on. You can find Gen. Douglas MacArthur and his staff peering out of a plane window at the Yalu River on the Chinese border. Pfc. Frederick M. Cox of Beaver Falls, Pa., standing guard over three North Korean prisoners. Close-ups of some spare auto parts that rusted in their packages. Aerials of the desolate, snow-covered mountain ridges around the Chosin Reservoir in Korea, scene of an epic retreat in 1950. Parachutists being sown in the sky on D-Day. Soldiers eating K rations. Bodies from the Malme'dy massacre in France during the invasion. Army doctors treating Korean refugees. Ruined villages. Shell explosions. Supplies stacking up on the beach at Leyte Gulf in the Pacific. GIs at the Bulge, their helmet straps hanging loose in the preferred fashion, their young faces unshaven and grinning hard soldier grins . . .

"It took us three weeks just to bring these all over from the Department of Defense depository at Anacostia," said archives technician Jim Trimble. "We already have 950,000 images from the Navy in here, and in a year or two we hope to get the Marine and Air Force pictures."

Trimble spends his lunch hours poring over the albums, reading the faded captions with a magnifying glass in search of famous names.

Dick Myers, chief of the archives' still pictures branch, said most of the requests for military photos come from weapons buffs or people who want group shots of their old units.

"Our Navy pictures, from the '20s to 1958, are the busiest item we have," he said. "We handle about 350 requests for copies every month. The Army has already broken them up into several collections, like unit photos, hardware, battle scenes, personalities, so the same picture may turn up in a number of places."

Eventually, the archives plans to put the newly acquired Army collection on videodisc, a technique used by the Air and Space Museum with the 100,000 Air Force photos it has been loaned. Those pictures have just been released for sale to the public on three discs. The advantage of a videodisc over videotape is that you can call up the picture you want from code coordinates without having to wind through the whole sequence.

"There's enough stuff here to keep us busy for quite some time," said Myers.