Here's the file to list the authors of the pictures, as
far as I (matju) know:

b001.jpg, r001.jpg:
  Eyewire Catalogue, 1999 or before. It should be checked
  whether there still exists a copyright on this, because
  the original provider has disappeared (bankruptcy??)
  several years ago.

g001.jpg:
  by Alexandre Castonguay, 1999 (?).

bluemarble.jpg:
  NASA (?)

lada.jpg:
  hungarian newspaper ad.

lena.jpg:
  Lena Sjööblom Soderberg, centerfold of Playboy 1972.11.
  Researchers in infographics have extensively used that
  picture without necessarily asking for copyright, and
  apparently Playboy doesn't mind.

lucida-typewriter-12.grid.gz:
  a grid(256,13,7) containing the Lucida Typewriter 12
  medium font.

opensource.png:
  modification of a World War Two poster. Both authors
  (original's and spoof's) are unknown to me. Should check.

rose.jpg:
  unknown origin.

ruby0216.jpg:
  photo from a conference about the Ruby programming language,
  held somewhere in Japan in 2003 or so. (?)

teapot.png:
  Researchers in infographics have also extensively used
  that picture (actually the wireframe model). This is
  (afaik) the original model, produced in the 1970's (?)
  by one such researcher, and then was rendered in the
  1990's using the Povray raytracer, and then bundled as
  teapot.ppm in Tcl/Tk, and finally in 2001 I grabbed
  that picture 

test.mpeg:
  unknown origin. Too small to be copyrightable.

tux.tga.gz:
  unknown origin.