This is an interesting portrait, since it appears to be that rather rare object: a submission to a Tumblr blog of an image anyone would be proud to post.
Tumblrs very often have a “Submissions” page – particularly if they’re po*n or semi po*n, and hope some bored teenager/housewife will send in shots of her assets once the appeal of Snapchat‘s evanescence has worn off (there are, by the way, about 300 million Tumblr blogs running currently). The image blog that received this as a submission, however, is dedicated to more arty erotica, with a lot of nudity and semi-nudity (so the image link below is only for 18+), but no exchange of bodily fluids – at least not male-female: and in fact there aren’t any males at all, as far as I remember. It’s Russian, with a high quality threshold, and brings a goth sensibility to (mostly) studio erotica. Just being a bit shadowy and in b&w often seems to meet the criteria, like this (not particularly gloomy) portrait.
The blogger does post appropriate younger girls’ portraits, like Cassie’s, but typically with a slightly dark ambience – like this by Teresa Queiros on Flickr:
……one of a lovely set featuring these mysterious twins (image link at the bottom).
You can see the appeal to Deadgirls: this definitely isn’t Anna Pavaga selling fashion styles.
The only mystery is Cassie’s portrait. I don’t know the Deadgirls archive well enough to know if she sent more, or gave any more details. The image doesn’t reverse search on Google or Yandex, so if it was a fake personal submission (it’s suspiciously well composed and lit) I can’t find another source. Let’s hope she appears as more than just a mysterious model in one image in the future – tho’ since this dates back to Feb 2013, there probably isn’t much hope left…