My wife has a photographic memory and you are right it does skew sequencing if she memorizes the information in the wrong way. It also does not adding in understanding of the information read.
She describes it this way she looks at the page and it imprints in her mind. The she pulls up the image and can read it in her minds eye. Almost like reading a page in book you hold in your hand. Most of her siblings have the same ability and because of it they did very well in school. Troubleshooting or figuring it out seems to be the weak spot for them as they relied on a crutch of memorization. I am almost the opposite I have to understand the topic to recall the information.
My son seems to remember the stats that are on many card like the backs of baseball cards. He is able to do this with anything that he wants to remember otherwise he does not remember it at all. I think he has some selective memory. There are times he gets things out of order but he catches himself and corrects it.
I'm surprised so many are saying they know someone who has a photographic memory and their a family member too! I don't think I've even come into contact with anyone with this ability. Maybe they just never told me they have a photographic memory but I thought this was rare.
I understand that there is a difference between an eidetic memory and a photographic memory. According to neuroscience EVERYONE has and eidetic memory, or I should say imprinting a brain pattern with absolutely every tiny bit of the 6 billion bits of information per second that our brain receives but it is the RETRIEVAL that is flawed in some people. I write in images more than just words so I've been told my memory is somewhat photographic but my recall is far from perfect.
I have exceptionally poor short term memory. I can forget what I'm doing from the table to the stove which is a short matter of 6 steps. I NEVER remember names unless I write them down. Generally I have to involve my hands and eyes together to remember anything at all or my hands, eyes and ears. One of the reasons I hated one college professor I had was that he read ver batum out of the text book and added a comment that was bound to be on the test about every 7 paragraphs and he would put information from the illustrations in the book on the test as well so we couldn't get away with only attending class or only reading our book. It made his lectures very boring.
However my long term memory has been recorded as exceptional. I can remember an event that happened when I was less than 1 years old, I remember dreams I had as young as 4 and I can describe the color, spacing and textures of the first home I walked in. The fact that we lived there for 9 years does not come into play because we changed the color and furniture layout several times. I can describe it from the viewpoint of a 2 year old. I've been told to remember that young is rare.
My wife can pull up the information for a few years if she is using it. If not it will fade in a few months. Images seem to last longer then text though.
My wife is the first person I knew with this and it seems my oldest son might be the same way also.