Original post here.
Bonus Image Provenance: I commissioned Bacchus at ErosBlog to research this image further, and he has come up with the following additional details.
Your image is the work of Japanese artist “Teston”, whose rudimentary home on the web appears to be here:
A thematically similar work can be found in one of his galleries:
And older verson of his website, now gone 404 but still in the Internet Archive, shows some additional images:
Again, thematic similarities:
Although there aren’t all that many artworks in his own galleries, it wasn’t hard to find additional galleries of Teston giantess artwork (including in some cases your image) in many of the usual places, with confirming “Teston” tags or description:
Bacchus is actively taking image research commissions, and if you have adult imagery you’re curious to learn more about, I encourage you to visit Bacchus’s introductory post for his image-searching service, where you can find details about how to commission him.