A man in a security vest is smiling for the picture.
Someone is posing for a photo.
A man is a type of someone, and posing for a photo is another way to say siming for the picture.
exists e1 x1 x2 x3 x4.(n_picture(x4) & for(e1,x4) & Actor(e1,x1) & v_smile(e1) & in(x1,x2) & n_vest(x2) & of(x2,x3) & n_security(x3) & n_man(x1))
exists e1 x1 x2.(for(e1,x2) & n_photo(x2) & Actor(e1,x1) & v_pose(e1) & n_person(x1))