I’ve found a colour woodcut by an unknown artist…
The picture shows either the ruins of a castle or a castle perched on a hill overlooking a wide bend in the river. At the foot of the hill lies a small village by the river. In the foreground are a few conifers.
Although one might think that a relatively large castle overlooking a bend in the river would not be all that common, unfortunately no information has yet been found.
Update 29 June 2026
Gerbrand Caspers, the author of the blog “The Linosaurus”, believes that the creator of the montage was Erwin Frommbach (1892–1975). Posts about him can be found on his blog: