thanks. between that fresco and the newly discovered reflective face, we can get a pretty good idea of what Narcissus was presumed to look like during that era.
Ovid, who describes Echo and Narcissus in the Metamorphoses, perhaps published in about 8 A.D., describes Narcissus hanging way over the water to admire himself, until he was just about flat in trying to get a better and better look at himself. Neither of these paintings choose that posture in the figures thought to be Narcissus. Artist’s prerogative, or an artist using stock human figure types.
http://ovid.lib.virginia.edu/trans/MetindexLMN.htm#Narcissus
Ovid was inspired by genres of earlier Greek poets. Vesuvius erupted in 79 A.D. The nouveaux riches of Vesuvius loved these stories for their walls.