I don't know if these books are the answer to what you wish
regarding a picture book for Mark Twain, but Milton Melzer (sp.?)
and Justin Kaplan have put out, respectively, -Mark Twain Himself-
and -Mark Twain's World- (or, possibly, -Mark Twain and His
World-), books that contain many pictures of Twain, friends, family,
associates, events, personalities of the times, and related items,
such as paintings, maps, blueprints of the Twain House, and photos
of buildings and cities pertinent to Twain.  The -Himself- book is
primarily pictures with some text; the Kaplan book is, basically, a
biography with pictures on most or facing pages.  Kaplan's book
contains many color pictures; except for the book jacket picture of
Twain, Melzer's book is entirely in black and white.

I hope that these books are a start, but you are right; we need more
and something more extensive.  Both of these books are now well
more than 20 years old.
John H. Davis, Ph.D.
English Division
Chowan College
Murfreesboro, NC