It should be noted that almost all the people that claim to have eidetic memory are full of shit. People who claim that they have eidetic memory, when scientifically tested, are in fact shown to be either lying (simple fraud), using memory techniques (Chess masters can only memorize legal chess boards, they can't chunk random ones) or idiot savants who specialise in specific memory tricks (drawing a skyline/memorizing books).
> A number of people claim to have eidetic memory, but only two people have been tested and documented as having a memory that is truly photographic. Most people showing amazing memory abilities use mnemonic strategies.
Source: http://en.wikipedia.org/wiki/List_of_people_claimed_to_posse...
> An example of extraordinary memory abilities being ascribed to eidetic memory comes from the popular interpretations of Adriaan de Groot's classic experiments into the ability of chess Grandmasters to memorize complex positions of chess pieces on a chess board. Initially it was found that these experts could recall surprising amounts of information, far more than non-experts, suggesting eidetic skills. However, when the experts were presented with arrangements of chess pieces that could never occur in a game, their recall was no better than the non-experts, suggesting that they had developed an ability to organize certain types of information, rather than possessing innate eidetic ability.
Scientific skepticism about the existence of eidetic memory was fueled around 1970 by Charles Stromeyer who studied his future wife Elizabeth, who claimed that she could recall poetry written in a foreign language that she did not understand years after she had first seen the poem. She also could, apparently, recall random dot patterns with such fidelity as to combine two patterns into a stereoscopic image. She remains the only person documented to have passed such a test. However, the methodology of the testing procedures used is questionable (especially given the extraordinary nature of the claims being made) as is the fact that the researcher married his subject, and that the tests have never been repeated (Elizabeth has consistently refused to repeat them) raises further concerns.
> With the questionable exception of Elizabeth (discussed above), as of 2008, no one claiming to have long-term eidetic memory has been able to prove this in scientific tests. There are a number of individuals with extraordinary memory who have been labeled eidetickers, but many use mnemonics and other, non-eidetic memory enhancing exercises.
Source: http://en.wikipedia.org/wiki/Eidetic_memory