Musannaf Ibn Abi Shayba 16:1072

Abu Bakr narrated to us, he said: Al-Hasan ibn Musa narrated to us, he said: Hammad ibn Salamah narrated to us, from ‘Amr ibn Dinar, from Salim ibn ‘Abdullah, he said: They used to see no harm in the images that were stepped upon. And Allah knows best.