Vaseline is good for helping tattoos not to dry out. It is a protectant, but not a nourishing cream such as A&D Ointment or Aquaphor.
Vaseline acts as a barrier to prevent moisture from escaping the top layer of skin, but it does not penetrate skin to keep the tattoo looking new in the long run. A&D Ointment or Aquaphor have ingredients that get under the skin's surface and nourish it, maintaining the tattoo for a long time. To keep a tattoo looking new, products with antioxidants and anti-inflammatory components sustain and rebuild skin layers while keeping tattoos healthy and more defined.