WHAT WOULD a picture be worth of Sen. Edward M. Kennedy taken with Helga Wagner, the mystery woman he called in the critical hours following Chappaquiddick?

What would a picture be worth of Prince Charles and Helga Wagner, taken at an event where she was his special guest?

What would a picture be worth of all three together?

What is known as a "photo opportunity" for all three of those pictures almost came together at the World Cup Polo Tournament in Palm Beach last weekend. But Sen. Kennedy, although scheduled to appear, didn't show up and there was speculation he may have gotten word from one of his nieces about the potential embarrassment.

It's possible, though, that someone got a shot of Prince Charles with Wagner. And that possibility has the international press scurrying around faster than shutter speed.

Ironically, Prince Charles was trying hard all Easter weekend not to give match-making mothers and the media any opportunity to catch him in camera range with any eligible, unmarried women.

Buckingham Palace had gone to extraordinary lengths to avoid speculative publicity about girls, according to sources who helped stage the events on Saturday and Sunday at the Palm 6Beach Polo and Country Club.

So what does Prince Charles do, all on his own, after all the protective protocol has been worked out, but invited Helga Wagner to be his personal guest.

Wagner became a matter of intense public curiousity here and abroad last month after she told The Washington Post about her Chappaquiddick connection.

A member of the international Jet Set and divorced from a globally active oil and shipping tycoon, Wagner had lived for awhile in England. So the British press has already had a field day in recent week about her past romantic relationship to Sen. Kennedy.

Wagner's friendship with the prince of Wales was also something that had escaped public notice. Learning of it had an electrifying effect on British journalists covering Prince Charles in Florida.

No one seems to know for sure how long or how well she has known him, although one published report claims that she met him four years ago while skiing in Gstaad.

Wagner, who looks to be in her 30s, is actually in her 40s. Prince Charles is 31.

Wagner's former mother-in-law is a leading hostess in Gstaad, according to friends in Florida. A sister-in-law is married to an Austrian baron and is part of the aristocracy that skis there.

Wagner, who now lives and works as a jewelry designer in Miami, showed up in Palm Beach last Saturday. The first anyone connected with the polo events knew of her presence was when Prince Charles called late in the afternoon from his bungalow with instructions for those in charge. Not only were they to invite Wagner to the dinner dance that night, but they were to put her at his table and to put her in the place of honor at his right.

On a Richter scale for royal family reverberations, this may not register more than Princess Maargaret's face-life or Princess Anne's husband kicking his horse.

But it is too soon to measure accurately.

The British press, not forgetting that another prince of Wales gave up the throne of England for a divorcee, isn't willing at this point to assume that Wagner's friendship with their future king is merely platonic.

Sen. Kennedy missed getting directly involved in the furor that has ensued. One of his nieces, Maria Shriver, daughter of Sarge and Eunice Shriver, also sat at the table with Prince Charles and Wagner on Saturday night.

Sen. Kennedy and his wife, Joan, were in Palm Beach, spending the holiday with his mother. They were not at the dance, but Sarge Shriver had picked up six tickets to the polo games the next day and Sen. and Mrs. Kennedy were expected to be in that party.

Joan Kennedy showed up on Sunday as expected, but her husband did not. At least a half-dozen different explanations for his absence were reported afterward in press.

Whether or not the politically savvy Maria Shriver alerted her uncle about Wagner is not known.

But on Sunday, Wagner showed up to sit this time at Prince Charles' left in his box. Photographers had been barred from the dance the night before and were not permitted to shoot in the direction of his box on Sunday.

Most new photographers, even if they had been willing to disregard the rules, would not have been in a position to catch Wagner with Prince Charles.

She sat in a different box until photographers were herded off, out of range, to await an awards ceremoney, before she moved to Prince Charles' side.

The British press has done everything but post a reward for any amateur photographers with a Nikon or an Instamatic who may have unknowingly gotten that shot.

Wagner has been under seige since Sunday. On Monday, reporters and photographers showed up at her place of business only to be told she had gone to South America on a sales trip.

The canny Brits staked out her little red Alfa Romeo, followed her home. A London Daily Express reporter claims she backed her car over his shoe in her haste to pack and bag and depart -- if not for South American, at least out of camera range.