a woman sitting down on a class smiling at the camera
A woman is holding a camera and about to take a picture.
There is a typo in this sentence.  A woman should not be sitting ON a class.  Plus, if she is taking a selfie, she can be holding the camera.   These sentences are not contradictory.
exists e2 e1 s1 x1 x2 x3 x4.(n_camera(x4) & a_topic(x1) & for(e1,e2) & at(e2,x4) & Actor(e2,x2) & v_smile(e2) & on(e1,x3) & n_class(x3) & a_down(s1) & Manner(e1,s1) & Actor(e1,x2) & v_sit(e1) & (x1 = x2) & n_woman(x1))
exists e1 p1 s1 x1 x2 x3 x4 x5.(a_topic(x4) & Topic(s1,p1) & Actor(s1,x5) & a_about(s1) & exists e2 x6.(Theme(e2,x6) & Actor(e2,x5) & v_take(e2) & n_picture(x6)) & (x4 = x5) & n_woman(x4) & a_topic(x1) & Theme(e1,x3) & Actor(e1,x2) & v_hold(e1) & n_camera(x3) & (x1 = x2) & n_woman(x1))