no goals
α : Type u_1
β : Type u_2
γ : Type ?u.54851
ι : Sort ?u.54854
ι' : Sort ?u.54857
f✝ : α → β
s t : Set α
f : α → β
hf : Injective f
eq : f '' s = f '' t
⊢ s = t
rw [← preimage_image_eq s hf, ← preimage_image_eq t hf, eq]