∀ {α : Type u_1} {β : Type u_3} {γ : Type u_5} [inst : DecidableEq γ] {f : α → β → γ} {b : β} [inst_1 : DecidableEq α]
  (s₁ s₂ : Finset α),
  (Function.Injective fun a => f a b) → Finset.image₂ f (s₁ ∩ s₂) {b} = Finset.image₂ f s₁ {b} ∩ Finset.image₂ f s₂ {b}