What was the miracle that happened to Kakasaheb Dixit involving a vision and a picture of Vitthal?

Chapter 4 narrates a remarkable experience of Kakasaheb Dixit. After his morning bath, while in meditation, Kakasaheb received a clear vision of Lord Vitthal. Later that day, when he went to see Sai Baba, Baba cryptically asked him, "Vitthal Patil had come, right? Did you meet him?" and advised him to "nail him down and make him steady." The full meaning of this became clear in the afternoon when a person from out of town arrived selling twenty-five pictures of Vitthal of Pandharpur. Kakasaheb was amazed to see that the image in the pictures was an exact replica of the form he had seen in his morning meditation. Realizing this was another proof of Baba's omniscience and grace, he lovingly bought one of the pictures and installed it for worship.