Show this stuff in LiveJournal, a blog, a blag, or Myspace (or rather, Yourspace) with these fancy text-a-ma-jigs:
<a href="http://BetaParticles.thecomicseries.com/comics/pl/74106"><img src="https://img.comicfury.com/comics/b8a917bf92e08f38b0752d59d19b811d931734834.gif" alt="Beta Particles - Eidetic-Man" border="0" /></a>
<br />
<a href="http://BetaParticles.thecomicseries.com/comics/pl/74106">Eidetic-Man</a>
Alternately, spam this stuff all over forums by including these fancy texty thingies:
[URL=http://BetaParticles.thecomicseries.com/comics/pl/74106] [IMG]https://img.comicfury.com/comics/b8a917bf92e08f38b0752d59d19b811d931734834.gif[/IMG] [/URL]
[URL=http://BetaParticles.thecomicseries.com/comics/pl/74106]Eidetic-Man[/URL]
... Or am I just thinking really hard?
So far as actually playing an instrument, that would be more muscle memory - which is a fairly closely related phenomenon.
I know how we could test for visual eideticism: try to tell me how many people are in the background of the picture of the books on the table.