If together, the images include both white knee pads and black knee pads only.
return images ;return knee  pads in  #1 ;return #2 that are white ;return #2 that are black ;return #3 , #4 ;return #2 besides  #5 ;return number of  #6 ;return if  #7 is equal to  zero
['select', 'project', 'filter', 'filter', 'union', 'discard', 'aggregate', 'boolean']