Original post here. This image was researched by Bacchus at ErosBlog as part of the “Γ commission.” The research was originally published at Hedonix as “Γ 025 – The Frog Elixir.” Here is what Bacchus found.
This artwork appears on the cover of the book Confessions of a Teenage Frog (Samantha Slade, Book 2) (1987). Google Books identifies the cover artist as Jodi A. Lee, and provides this summary of the book:
Samantha is running for class president against the prettiest girl in school when she makes the mistake of drinking a “greatness potion” cooked up for her by Drake, one of the two “monsters” she babysits. But instead of turning her great, the potion turns her into a talking frog!