Was there an ancient cult of worshiping one's own reflection?

Question

Are there any sources about an ancient cultic worship of one's own reflection (in water)? Have historians found any evidence of such a phenomenon?

The idea is found in some early Jewish commentaries: The Bible relates that Gideon amassed an army of 32,000 men, but God dismissed the idea of defeating the Midianites with such a large force because it would not be apparent that the victory came through Him. Instead, the army was eventually whittled down to 300 men by way of a unique litmus test: Gideon took his men to drink from a pond of water and God commanded that all those who kneeled while sipping from the water, were disqualified from Gideon’s army (Jud. 7:1–8). The classical commentators have explained that only those men who lapped with their hands to their mouth to drink water were considered righteous enough to join the army, but those who kneeled were not. Those who kneeled displayed idolatrous tendencies by revealing that they were accustomed to kneeling. R. David Kimhi explains that they either bowed to Baal or to their own reflection in the water.

The notion of people worshipping their own reflection is found in several places in rabbinic literature: The Talmud (TB Nedarim 9b) tells of an individual who became a Nazirite because he saw his reflection in the water and was inspired to commit a sin, which some commentaries explain means that he wanted to make himself into a god (see Shitta Mekubetzes there and Pirushei u-Nimmukei Rabbeinu Ezriel to TB Nazir 4b). Elsewhere, the Talmud (TB Chullin 41b) outlaws slaughtering an animal next to a pond of clear water because it looks like one is slaughtering the animal as a sacrifice to his own reflection.

Answer 1

I’m sure you are familiar with the myth of Narcissus a hunter from Thespiae in Ancient Greece who was known for his beauty. Son of the river god Cephissus and nymph Liriope. He disdained those who loved him. Nemesis noticed this behavior and attracted Narcissus to a pool, where he saw his own reflection in the water and fell in love with it, not realizing it was merely an image. Unable to leave the beauty of his reflection, Narcissus lost his will to live. He stared at his reflection until he died.

Evidence for a cult of Narcissus(Chapter 1 Tracing the Narcissus Myth see page 21-22) in Boeotia(ancient Greece) is very strong, seeing that shrines existed at Thespiae, Oropus, Tanagra, and perhaps Eretria.

Answer 2

No. Your examples along with legend of Narcissus clearly show that such behavior is self-destructing and there is no evidence, and to be a cult there would have to be organization and leadership; not likely among a group of self-absorbed individuals.
But,
Yes. Man made in the image of God (whoever came up with that was no doubt quite impressed with himself), body is a temple, all prophet types railing against vanity and the appearance of goodness and piety while being self serving. Jesus goes on about it in Matthew 5 & 6, against the desire to appear good, to be seen doing good works. That wouldn't have been necessary if it weren't so common.
  While reputation is an important biological fact of social creatures, "look good" and absorption with self-image are the dangerous side of it.
   I have repaired many computers for people over the years and know that one thing to expect on young people's devices, especially teen women, are hundreds of self-pics, thousands if they've had it long enough. Perhaps it's partly natural, partly cultural, perhaps harmless. But when they or anyone chooses their look-good over the well being of others we've got a problem. It could be something small, blaming another for action, with no serious consequence or worse, with serious harm coming to another as a result. Worse yet is when they don't own up to an inaction or action with grave consequences to the community (starting a fire that gets out of control and not alerting anyone so as not to be held responsible, infecting a well by hiding sewage or disposing of other things in it, leaving the barn door open, etc).
Does this constitute "love" of self image? Willing to sacrifice any and all for the one they love (their appearance)? Once again, such a group wouldn't last long. Vanity is also an epithet that the ancient world threw at each other consistently. The Greeks have the tale of Achilles anger over hurt vanity (but didn't seem to quite grasp the point) while using it as the top complaint against the Persians (not bad government, so called lack of freedom (Greeks had lots of slaves), just vanity. A sort of "look at them looking at themselves, not us doing the same".
  So no, never a cult dedicated to worshipping self reflection. But Yes in that it has been an ancient theme and every cult (and most groups) think they are different and special, love their own group, think less of others, and generally people obsessed with status/ranking/look-good within groups. We are the only social animal that can fake credentials, appear to be what we are not. We need maintain vigilance against this and having stories about self-absorbed people coming to a bad end is part of that, of promoting the long term good of the group over short term self advantage.