This is the most unusual portrait of Saint Martin I’ve come across so far. First of all he looks fairly female. Secondly, the beggar is taller than him, even though the saint is sitting on a horse with bad acne. This is a fresco from the San Marti church in Puigbo (Spain). The fresco dates from the 12th century.
The more common images of Saint Martin depict him as either a man in fancy contemporary clothes or (more true to the original saint) as a soldier in Roman armour, with the begaar leaning on a stick and looking up, such as this one: