∀ {C : Type u} [inst : CategoryTheory.Category.{v, u} C] {F F' : CategoryTheory.Functor C (Type w)} {ι : Type u_1}
  (G : ι → CategoryTheory.Subfunctor F) (f : F ⟶ F'), (⨆ i, G i).image f = ⨆ i, (G i).image f