What is the story behind Kakasaheb Dixit's vision of Vitthal and the picture he bought?

The story of Kakasaheb Dixit's vision is a notable account of Sai Baba's omniscience. According to Chapter 4, after his morning bath, Kakasaheb had a vision of Lord Vitthal during meditation. When he later went to see Sai Baba, Baba surprised him by asking, "Vitthal Patil had come, right? Did you meet him?" and advised him to make the vision steady. Later that day, a seller arrived with twenty-five pictures of Vitthal of Pandharpur. Kakasaheb was amazed to find that one of the pictures was an exact replica of the form he had seen in his morning vision. Remembering Baba's words, he purchased the picture with great love and installed it for devotional worship.