This painting comes from the same house as the on posted yesterday (House of Loreius Tiburtinus / House of D. Octavius Quartio), but here’s another myth depicted. Notice the boy and more importantly his reflection in the water beneath him!
Here we see Narcissus who is looking at his own reflection in a pool of water. There are several versions of this myth, one tell us that the gods made him stay at the pond until his death as a punishment for rejecting everyones love to him. The Roman author Ovid write that he killed himself when he realized that he would never be loved in return by his image.
Read the full story about Narcissus here.