How Washington thrives on uproar, be it Watergate, Koreagate, Billgate or, to cite yesterday's wonderfully fresh artistic ruckus, the Controversy of the Carter Administration Photos.

"Controversy can be a good thing," said Joan Mondale, smiling pleasantly from the stairs at the vice prsident's residence. "Nothing is worse than going unnoticed."

And nothing did. A good 125 people jabbered through a reception at the Mondales' that honored the photographers who'd taken the disputed pictures, and then, two hours later, hundreds more turned up at the National Portrait Gallery to scrutinize it all for themselves.

"Good picture of you, Bob," Eductation Secretary Shirley Hufstedler said to Robert Strauss, chairman of the Carter campaign. "It looks like you're saying, 'I have now raised enough money to redeem Texas.'"

"And, now if we could only get California," replied Strauss.

But the picture controversy: It started nearly three years ago when Jimmy Carter decreed that members of his administration, in preserving themselves for history, should have photos taken instead of portraits painted. Cheaper, he said.

Some balked, a few wouldn't sit still, and a few were fired for matters wholly unrelated to film versus oil. But finally, a full year late, the exhibit has opened. And not everybody loved it.

Last night, standing by the picture of former Health, Education and Welfare Secretary Joseph Califano you would have heard:

"It's a riot. Doesn't he look like he's selling something? Like 'Try this cheese -- you'll love it.'"

Secretary of State Edmund Muskie's likeness, done by his 31-year-old son Stephen, elicited:

"I think it's godawful."

"I like it. Very alive, very warm."

"Sort of looks like he's been out fishing for the day."

And for former commerce secretary Juanita Kreps:

"It's emphasizing the woman too much. Why do we have to have the roses?"

"It's wonderful and soft."

"I think it looks like Nancy Reagan."

The events celebrating the exhibit opening began during the late afternoon at the vice president's home, where Joan Mondale said hello to guests on the big wooden porch. A spotted cat walked up the driveway, another scratched himself at the foot of the stairs, waiters served stuffed zucchini and a pianist played "Something," by the Beatles.

The home, unlike the White House, is really a home; the furniture looks like people sit in it and there's an old swing hanging from a front-yard tree.

Still, things started stiffly. Swing or not, the matchbooks in a bowl on a table still said "The Vice President's House" in formal letters, so people acted accordingly. But then they'd see somebody like photographer Jill Krementz or author Kurt Vonnegut and forget all about it.

Vonnegut was talking to former transportation secretary Brock Adams, who was messily fired during the Cabinet purge of 1979.

"Funny," said Adams, answering a question about what it felt like to be at a reception celebrating a picture of himself in a job that ended not very nicely.

"Well, nobody's ever a Cabinet member forever," offered Vonnegut. "But it was sort of a sore-headed departure, wasn't it?" Denfense Secretary Harold Brown was there to view his own living color protrait as well. "What we need is a cease-fire," he said of the war in the Persian Gulf.

Out on the porch, Krementz, who took pictures of four administration members -- and who is also Vonnegut's wife -- was taking snapshots of Joan Mondale with a small Olympus. "For my scrapbook," she said. On Monday, she was down form New York taking pictures of Walter Cronkit and Walter Mondale at the White House dining room.

"I get a kick out of taking a picture of the helping themselves to the salad bar," she said. "I just don't thingk of the vice president as helping himself to a salad bar."

Running down the driveway was Energy Secretary Charles Duncan, who's worried about U.S. oil cutbacks that may result from the Iran-Iraq conflict. "Continugency planning is just something you have to do," he said.

Mingling indoors was Marvin Sadik, director of the Portrait Gallery. And did he like the show?

"Some of it," he responded. He looked uneasy. "They were rehearsing me in the car on the way up," he said.

Then everybody went over to the gallery, only to wind up waiting in a hallway and drinking too much white wine before Rosalynn Carter arrived. Treasury Secretary G. William Miller amused himself by talking to George de Vincent, who'd taken his photograph.

"You were very easy," de Vincent said to Miller.

"You know I'm just a pussycat," Miller replied.

"Really," de Vincent said to a reporter, "he was very good. Surprised the hell out of me."

At 6:53 p.m. the crowd parted. The first lady. She went into the tiny exhibit room with Joan Mondale, the picture takers and picture takees. Everybody else had to wait outside.

When she came out, she said: "I think this is very appropriate for now." Also: "I think I like the one of Patricia Harris." And that was it.

Then everyone else piled in, in shifts. Vonnegut came out early. "They've used up all the oxygen in there," he said.