User blog comment:Jane St. Valentine/Fan art, or official images?/@comment-4854061-20160521095553/@comment-3193686-20160522090737

Thanks for letting me know.

Upon further investigation, I've found that the digital painting of the Rumbler was commissioned by NightDive Studios for their re-release of SS2, as confirmed in the images description on DA. The artist in question also drew the Midwife, though made no mention of being commissioned for it. The "Hiding in the Shadows" painting was done by Jason Burhans (perhaps he also goes by boxxman), though there is no confirmation of it being anything beyond fan art.

I can't determine the validity of any other images beyond the sketches with the Irrational Games/Star Insurance Company watermark. Considering that they allegedly come bundled with the Steam/GOG files though, I can assume they're all legit at this point. I'll reinstall SS2 on my system soon and check them out to see if I can figure out the remainder of the sources.