There is definetly an evolution in Author's Photos. In the beginning of course, in the 4th millennium BC in Mesopotamia with the "proto-cuneiform" writing, an image of an author accompaning his work wasn't even conceived, much less the practice. Although, there have been hand prints found next to cave drawings, which can be seen as the combined signature and and portrait of the artist/author.
Early authors such as Plato (around 428BC - 347BC) and Sun Tzu of "Art of War" (from around 722BC -221BC) at least had statues of themselfs. Up until the medieval era, men dominated the literary field; that is, until Christine de Pizan became the first professional published female, although she doesn't have a statue, she does have a beautiful portrait painting. Today these author's images may be seen on the front cover of their published works.
Not all books have Author's Photos, some just have "About the Author." And there are countless books without any reference to the author besides "by ___________". Jane Austen for instance never had a professional portrait painted; her sister Cassandra though did do a couple of sketches, and there is a silhouette; since then several attempts have been made to reconstruct what Jane may have looked like. Uh oh, I've just did a fopaux, and assumed familiarity and used Miss Austen's first name (it's an inside Janeite thing). :^)

Some authors have been very creative and illustrated their image, like Robert E. Stanley Sr. of "Northwest Native Arts: Basic Forms, and did his illustration in formline (a Northwest Native Art style). Frederica de Laguna borrowed regalia for her photo, for her edited with additions edition of George Thornton Emmons' "The Tlingit Indians." As it turns out, I did both; on "Legends in Wood, Stories of the Totems" I borrowed my great-grandmother Hannah Cogo's Eagle button blanket, and my grandmother Florence Meilke's spruceroot hat; on "Coloring Alaska, the Greatland on a Summer's Day" I had drawn the picture from "Legends...", who knows there's probably purple crayon all over my face right now, lol.
A great many authors will have a professional photo taken for their book. Salt Publishing.com utilized a funny page on "10 Ways to Take a Bad Author Photo" to emphasize the importance of a good photo. Julie Kramer of "Stalking Susan" checked out other author's photos in her local bookstore, and since she is a television news producer, she had her cameraman/friend do her photo, after her professional makeup artist worked her over, so she could aquire that "edgy" "thriller writer" look:
(Wednesday, July 16, 2008 Stalking An Author Photo http://workingstiffs.blogspot.com/2008/07/stalking-author-photo.html).
There are a couple of books on Author's Photos:
Writers: Photographs
by Nancy Crampton, & Mark Strand
Author Photo: Portraits, 1983 - 2002
by Marion Ettlinger (Photographer)
Why obsess on an Author's Photo? With increasing pressure on authors to have a good photo, and as Martha Woodroof's NPR Morning Edition pointed out in "Author's Photograph Essential In Marking A Book", the author's photo IS part of todays book, and is part of the deciding factor of future readers.

So, while redesigning "Legends...", my original photo will be represented somewhere in the book, but am really courting the idea of a new photo.
For "Transformation Masks" the photo used is one taken just prior to setting off to the 2005 Der Ring des Nibelungen. My editor and friend H. James Birx was seated beside me in the original photo. When relating this story, he said that he had
been "edited out". :^) (the photo on the top of the page)
Well, with digital camera in hand, I'm off to see if I can get a good Author's Photo!
Until Next Time,
Pamela