No, it was done for the first Ewok movie in the mid 80s: Little Cindel's parents get kidnapped by this giant called the Gorax, but get rescued by Wicket's people. This idea for a shot was never used, but I wish it had! Man, I gotta rent the DVD of the Ewok movies to get inspiration for Ewok fighting!
It definitely appeared in The Illustrated Star Wars Universe, which contained a mixture of preproduction work by McQuarrie as well as finished pieces commissioned specifically for the book. The painting in question could fit into either category, but it appears to be much more "finished" than a lot of the other concept paintings McQuarrie did. I suspect it was done for the book.