This is a poem by Robert Service. A poem which I loved to read as a kid. I think it addresses with humour the thin line between appearance and reality.
I haled me a woman from the street, Shameless, but, oh, so fair! I bade her sit in the model’s seat And painted her sitting there. I hid all traces of her heart unclean; I painted a babe at her breast; I painted her as she might have been If the Worst had been the Best. She laughed at my picture and went away. Then came, with a knowing nod, A connoisseur, and I heard him say; “’Tis Mary, the Mother of God.” So, I painted a halo round her hair, And I sold her and took my fee, And she hangs in the church of Saint Hillaire, Where you and all may see.