the subject of a lecture to be held Tuesday evening at the Bermuda National Gallery. "Sir Joshua Reynolds and Thomas Gainsborough -- Friends or Foes?'' is the title of Mrs. Maurine Cooper's talk, which will be illustrated with slides of the artists' work. A limited number of tickets at $7 ($5 for members) are available for the lecture which starts at 7.30 p.m., from the gallery or at the door. Above, "Mr. and Mrs. Andrews'' by Thomas Gainsborough.