A gathering of people taking pictures.
Some people are taking pictures.
A gathering of people implies that there are multiple, or some, people.
exists e1 x1 x2 x3 x4.(a_topic(x1) & of(x1,x2) & Theme(e1,x4) & Actor(e1,x3) & v_take(e1) & n_picture(x4) & (x2 = x3) & n_people(x2) & n_gathering(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_take(e1) & n_picture(x2) & n_people(x1))