Putti (singular putto) are representations of a small naked boy, often with wings. They have several other names, including Cherub (typically in a church setting), Amorini, and Cupid. They often look distinctly overweight!
They can appear in paintings, sculpture or plasterwork.
Local examples (click to enlarge)
Cathedral nave, south wall
Tower of Mary Magdalen church, Burgate
Christ Church gates, cathedral
Queen Elizabeth Guest Chamber, High Street
Cathedral – Martyrdom