My original tumblr post was here. This illustration was originally posted by Vintage Geek Culture with the explanatory text Not Pulp Covers. There is an index page for works by the American artist and writer Richard Sharpe Shaver (1907-1975) here.
Tumblr favorite #2695: A queen and her attendants
It might be from one of these issues:
http://www.collectorshowcase.fr/IMAGES2/amaz_4803.jpg
http://www.collectorshowcase.fr/IMAGES2/amaz_4809.jpg
(I’ve actually had both of these pulps on my eBay “Watch” list in the past, but I haven’t bought either one yet. I have read 5 other Richard S. Shaver stories, including “I Remember Lemuria”.)