Image change was what several members of the official party had in mind as they set out. The president wanted to be re-seen as a peacemaker -- but tripped over his sword in a Cold War speech in London. The first lady wished to be noticed for her good works at drug centers -- but upstaged herself by wearing black knickers at Versailles.

Only Secretary of State Alexander Haig, who went along expecting nothing, found a new role abroad. It was thrust upon him.

The president's people had seen the journey as one long "photo opportunity": the president with the Swiss Guards at the Vatican; the president horseback riding on the velvet lawns of Windsor Castle with the queen of England. But when they arrived in France, they found that European leaders are dismayingly into words, and, more astonishingly, their own.

After the economic summit, Margaret Thatcher, Helmut Schmidt and their ilk hurried around to tell the reporters of their countries about what had happened. It was unthinkable to throw the president into such a situation and equally unthinkable to field the everyday presidential flacks against such heavy hitters.

So Alexander Haig became the official mouthpiece. He was either an exalted press secretary or a surrogate president. The one thing that was sure was that he was having a wonderful time, and so was the press.

For reporters it was often the day's only encounter with a person of consequence. The president's schedule is chopped up in such tiny bits that one "pool" of reporters may follow him to the steps of the castle, another may walk down the corridor behind him, and a third may be allowed to stand for five minutes in the room where he will be settling the affairs of the world.

Haig obviously didn't tell everything he knew, but at least he was in a position to know, and he revealed an antic side to his nature hitherto well concealed.

He had to open each session with a tribute to the president and how well he had performed on that particular day. Once that was out of the way, he went on to give his own views.

His Maggie-and-Jiggs with United Nations Ambassador Jeane Kirkpatrick had followed him across the ocean. The muddle over the U.N. vote on the Falklands -- she received his instructions too late -- greatly embarrassed the president, but entertained Haig no end.

The press hammered away at him at the briefing center at Grosvenor House in London. Had he spoken with Kirkpatrick the night of the vote?

The secretary's blue eyes gleamed. "I talked with her not once, but twice," he said. He held up two fingers and waggled them playfully. "Twice," he whispered.

He has always been lucky in his enemies. Before Kirkpatrick, there was Richard V. Allen of the watches and the guerrilla warfare. Kirkpatrick is, if anything, even better. Her Argentine sympathies are well known and her attacks made Haig a hero in London.

He was absolutely delighted when Kirkpatrick stirred the pot again by making provocative remarks about American diplomats -- "a bunch of amateurs" -- and American diplomacy -- "inept."

When asked about it, Haig said happily, "At times it is even brilliant, and at times it is even stupid."

By the time he got to Bonn all traces of his former self, the heavy breathing, polysyllabic, syntax-mangling martinet, had pretty well disappeared. One afternoon, as he was grinding through his daily report about the president, he used the word "criticality." There were groans and hoots from the scribblers.

Haig, stopped, raised his eyebrows: "You didn't like that?" Amid the continuing uproar, he murmured defensively, "Eisenhower used that word, I am sure." He began the sentence over again: "The president emphasized the importance of achieving the zero option."

At journey's end, the Middle East crisis had invaded the trip. Haig was a central figure. Would he go to Israel? Why did we have so little control over an ally? Another instance of the president's limited power was being vividly demonstrated just across the Rhine. Out of his sight and hearing, one of the largest crowds in postwar Germany had assembled to protest the arms race. Some 250,000 peaceable people carpeted the hillside, watched over by amazingly benign German police, who helped them lift their bicycles over the barricades.

Haig had nothing to say about the demonstrators. He does not approve of them. He shares the president's feeling that the German peace movement is excessive. When he complained to Chancellor Schmidt about it, Schmidt rejoined drily that the world should be glad that the Germans are now passionate for peace instead of war.

Haig plainly made himself indispensable on the European trip. He might make himself even more so if he could explain to the president that, in Germany, he is dealing with a deprogrammed nation.Mary McGrory's column appears in The Post three times weekly.