Summarizing both sides of story:
In July 1999, Mullah Mohammed Omar issued a decree in favor of the preservation of the Bamyan Buddhas. Because Afghanistan's Buddhist population no longer existed, which removed the possibility of the statues being worshiped, he added: "The government considers the Bamyan statues as an example of a potential major source of income for Afghanistan from international visitors. The Taliban states that Bamyan shall not be destroyed but protected." 
Afghanistan's Islamist clerics began a campaign to crack down on "un-Islamic" segments of Afghan society. The Taliban soon banned all forms of imagery, music and sports, including television, in accordance with what they considered a strict interpretation of Islamic law .
In March 2001, according to Agence France Presse in Kabul, the decree declared, "Based on the verdict of the clergymen and the decision of the Supreme Court of the Islamic Emirate (Taliban) all the statues around Afghanistan must be destroyed. All the statues in the country should be destroyed because these statues have been used as idols and deities by the non-believers before. They are respected now and may be turned into idols in the future too.
Then Taliban Ambassador-at-large, Sayed Rahmatullah Hashemi, said that the destruction of the statues was carried out by the Head Council of Scholars after a single Swedish monuments expert proposed to restore the statues' heads. Hashimi is reported as saying: "When the Afghani head council asked them to provide the money to feed the children instead of fixing the statues, they refused and said, 'No, the money is just for the statues, not for the children'. Herein, they made the decision to destroy the statues"
On April 19, 2004, in an interview to a Pakistani journalist Mohammad Shehzad, Mullah Mohammad Omar said the following, "I did not want to destroy the Bamyan Buddha. In fact, some foreigners came to me and said they would like to conduct the repair work of the Bamyan Buddha that had been slightly damaged due to rains. This shocked me. I thought, these callous people have no regard for thousands of living human beings — the Afghans who are dying of hunger, but they are so concerned about non-living objects like the Buddha. This was extremely deplorable. That is why I ordered its destruction. Had they come for humanitarian work, I would have never ordered the Buddhas' destruction."