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I haven’t been able to garner too much in the way of provenance on this image, except that it appears to be part of a painting that once graced the cover of novel written by the prolific German horror author Jürgen Grasmück (1940-2007) who wrote under a variety of pen names. This cover was apparently part of a series he wrote called Macabros under the pen name (one of many he used) Dan Shocker. The image is reblogged from this 30 May 2016 post at Infernal Wonders.
You’ll find the cover here:
http://www.coverbrowser.com/covers/macabros
…along with a bunch of others.
Elixier der Verdammnis or Elixir of Damnation.