Video released by the Crown Prosecution Service (CPS) shows Spellow Library set on fire and police in riot gear during violent disorder in Liverpool.
Violence broke out on County Road on Saturday 3 August, following days of unrest around the UK.
Police have made almost 500 arrests in connection with disorder following the killing of three young girls in Southport 10 days ago.
There were 21 convictions on Thursday, prosecutors said, and more rioters are facing jail in the coming days as suspects are fast-tracked to appear in court.
