Out of love for a red princess...and what should have been (and for those that weren't aware of the books!). Here's a link to an amazing site chock full of fascinating ERBdom art and interest: ERB Illustration.
Raise your hand if you knew Frank Schoonover painted Tharks?
And EIGHT galleries of Tharks: Thark Galleries.
Cover (first edition I believe?)
And I believe this may actually be J. Allen St. John (incorrectly credited online)