THE KNOCK ON HER DOOR ONE MORNING IN NOVEMBER of 1969 was the one every military spouse dreads. "I could see the light shining on his cross," recalls Ivy Spencer Bigbee of the Army chaplain who arrived at her Savannah, Ga., home. Her husband, Army pilot Jim Spencer, in Vietnam for only three months, had died after his helicopter had malfunctioned and crashed. "I cried," she recalls. "Then a few weeks later I picked up a camera and took photos at the grave site. It was a way of picturing my grief."

Now Bigbee's photography has come full circle. On Memorial Day, the Postal Service unveiled a POW-MIA commemorative stamp bearing her photo of a set of military dog tags. Bigbee, 48, was chosen to take the picture by a Postal Service art director who knew of her meticulous work—and her own tragic association with war. In Washington for a White House presentation of the stamp, Bigbee attended a tearful ceremony at the Vietnam Memorial with Navy Lt. Anthony Bigbee, 27, the son she had with Spencer two years before he was killed. Spencer "was not an MIA or POW," she says, "but he remains missing in my life. Every day is Memorial Day."

Childhood sweethearts, Ivy and Jim met at age 14 at Oscoda (Mich.) Area High School. In 1966 they married, and Jim, 19, enlisted. Three years later he was sent to Vietnam. Grieving after his death, Ivy went to a friend's slide show. The floral images struck a chord, and she bought a camera. "When Jim left for Vietnam," she says, "the world seemed dark. The camera opened it back up. I could see clouds, trees, everything."

Eighteen months after Spencer's death, that world was brightened by a new husband, Dr. John Bigbee, now 53, and their son Adam, 23. Still, says Ivy, "when you marry after losing someone, the person you've lost is not canceled out."

A few years ago, Bigbee began to concentrate on her photography full-time. Today her portfolio includes portraits of David Bowie and Ted Kennedy. "You can say my career was formed out of tragedy," she says. "But I would have traded it in a minute to have things turn out differently."