Cartoonist Thomas Nast, who died in Ecuador in 1902, did not
illustrate _Mark Twain's Burlesque Autobiography_.  That book was
illustrated by Henry Louis Stephens, a former owner and art editor of
_Vanity Fair_. Stephens was popular as a cartoonist before Thomas Nast
dominated the field and their work does look similar.

There is a good entry on Thomas Nast and his acquaintance with Mark
Twain in Kent Rasmussen's _Critical Companion to Mark Twain_.

Barb