Sometimes even the best efforts of White House image makers can't equal the results of a simple mistake.

Take last Monday night's photograph of President Reagan kissing Patricia Guerra at the Nicaraguan Refugee Fund dinner. The little girl, who presented Reagan with a picture of refugee children, was introduced as "an 8-year-old Nicaraguan refugee." To White House planners, the dinner was the perfect beginning to Reagan's drive for Congressional approval of $14 million dollars in aid to the Nicaraguan contras, and the picture, which was captured by a large crew of photographers, couldn't have been better.

Except Patricia isn't a refugee.

"It was a straightforward mistake," said Patricia's mother, Thelma Guerra, yesterday. Patricia was born in the United States, lives in Washington, and her parents have been in the United States for more than 15 years. Thelma Guerra works at the World Bank and Edgard Guerra at the Inter-American Development Bank. "It clearly stated in the dinner agenda that she was giving this picture to President Reagan 'on behalf of' Nicaraguan refugee children."

But master of ceremonies and former ambassador to Switzerland True Davis thought she was a refugee and, after his introduction, so did the 600 guests.

"She was offered to me as the genuine article," said Davis yesterday. "They said they were going to have a very attractive young lady who was a refugee who was going to give this picture to the president and when she appeared, I assumed that's what she was."

NRF executive vice president Alvaro Rizo Castellon said yesterday that Davis had misunderstood. "We never said she was a refugee."

Carter Clews, whose public relations firm, Clews and Co., handled publicity for the dinner, said of Davis, "I think he misstated that -- I guess for the same reason he sang the national anthem when Jose Feliciano was there to do it."

Davis didn't realize Feliciano was supposed to sing, and so he led the audience in an a cappella version of "The Star-Spangled Banner."

"I really thought the better picture was of the guy who was burned, standing with the president," said Clews, referring to a refugee who was said to have been burned by Nicaraguan government forces, "but I guess people like little kids. I don't know if it would have gotten equal attention if True had stated it correctly."