Please accept my blessings. I am in due receipt of your nice letter dated 10 February, 1970, and I am very glad to note how you are eager to understand this science of devotional service to Krsna or Krsna Consciousness.
Regarding your questions about the difference between the picture of Krsna and the Deity, Krsna is equally there in both these forms. Krsna is so kind that he agrees to appear, for the benefit of the conditioned soul, in eight different kinds of forms. Such form is called arca or the form of the Lord manifested through material agency as metal, earth, wood, painting, stone, jewel, drawing, and mind. The arca is accepted as incarnation of God, and is worshiped by regulations. Generally the installed Deities are so worshiped and the regulative principles should be strictly followed in regard to Them.
I am very happy to learn that you are finding the Detroit atmosphere so blissful, and actually the more you engage yourself in the sincere service of Krsna, the more you will find yourself always blissful.
So far your dreams are concerned, it is very nice that you are thinking about Krsna Consciousness even while sleeping. Krsna is so nice that we want to remember Him even more than twenty-four hours daily. Regarding instructions from the Spiritual Master, there is no need of taking instructions spoken in dream while the Spiritual Master is still present. Lord Jagannatha is very kind, and He can also appear in mind in His own form, so why not in your dream.
I hope that you are trying to follow the regulative principles and that both you and your husband are chanting your beads regularly daily. These two duties are essential for advancement in Krsna Consciousness, and if they are made the center of our activities, then Krsna will begin to answer all questions from within how to become further advanced in His loving devotional service.