Sahih Muslim Book 4, Hadith Number 2115.

Chapter : Commandment in regard to the levelling of the grave.

Abu’l-Hayyaj al-Asadi told that ‘Ali (b. Abu Talib) said to him: Should I not send you on the same mission as Allah’s Messenger (may peace be upon him) sent me? Do not leave an image without obliterating it, or a high grave without levelling It. This Hadith has been reported by Habib with the same chain of transmitters and he said: (Do not leave) a picture without obliterating it.