no goals
C : Type u
inst✝⁴ : Category C
X✝ Y✝ Z✝ : C
f✝ : X✝ ⟶ Y✝
inst✝³ : HasImage f✝
W X Y Z : C
f : W ⟶ X
inst✝² : HasImage f
g : Y ⟶ Z
inst✝¹ : HasImage g
sq : Arrow.mk f ⟶ Arrow.mk g
inst✝ : HasImageMap sq
⊢ (imageSubobjectIso (Arrow.mk f).hom).hom ≫ image.map sq = imageSubobjectMap sq ≫ (imageSubobjectIso g).hom
erw [← Iso.comp_inv_eq, Category.assoc, ← (imageSubobjectIso f).eq_inv_comp,
  image_map_comp_imageSubobjectIso_inv sq]