Why baha'is are not allowed to see the pictures of baha'u'llah?

As a Bahá'í youth, I remember not being impressed with the photographs I had seen of Bahá'u'lláh. Having grown up with charming images of `Abdu'l-Bahá, my expectations were high, and unfair to Bahá'u'lláh.

Portraits of `Abdu'l-Bahá are as common as the Virgin Mary in Bahá'í households, and they have guidelines for posting these portraits in a respectful manner. In spite of this idolatrous practice, Bahá'ís consider themselves special for not displaying portraits of Bahá'u'lláh!

I don't intend to criticize Bahá'u'lláh for his lack of physical charm. There is certainly no absolute need for a Manifestation of God to have a warm, charming appearance, but when I hear Bahá'ís wonder at the attractiveness of `Abdu'l-Bahá, I am moved to ask, why do you place significance on such matters?

I can't help but be skeptical regarding the motives behind the Bahá'í prohibition against portraits of Prophets. Given the Bahá'í affection for graven images, I'm inclined to wonder whether the prohibition would have ever been laid down had Bahá'u'lláh been better looking.

Bahá'ís are told not to keep photos of their Prophets because such photos could too easily become idols; believers would focus on the appearance of their prophet, and be distracted from his message.

Yet, the anticipation of Bahá'ís to view the one Holy Image in the International Archives Building in Israel is only heightened by that prohibition of graven images, and Bahá'ís shudder at the prospect of seeing the image of Bahá where they ought not, as though the image itself has some kind of ominous power!