I'm thinking of an illustration because the story contains many fantastic elements. But I also like to be convinced of alternatives.
Here's what I imagine:
The woman in white should be in the center of the cover. She stands at night in a forest or in a clearing or on a path in the forest. You can see her from behind as she looks over her shoulder (or something like that). Important fo me: It should create the impression that she is asking the viewer to follow her into the mysterious forest.
The woman should not be too close in the foreground.
It is not necessary to recognize her face. She is young, attractive and mystical. Her white dress could be gray and half crumbled because of age. Maybe she can levitate above the ground? (she is a ghost!).
From the forest a mysterious light could shine. Moonlight and fog would of course be possible too.
As for the color scheme, it should create a feeling of... lets say 'pleasant scare'. It's a classic scary story for today's readers.
The title is: Phänomena
(barely used german plural of phenomenon)
Author's name: S. G. Felix
(should be rather inconspicuous)
I need a space for the barcode on the backside (attached).
Dimensions: I have taken a screenshot for the dimensions of the cover.
Cutting edge top / bottom / outside 0.50 cm
Spine width 1.92 cm
Overall width with cropping margin 26.92 cm
Height with cut edge 20.00 cm
(Width (front/back) without trimming edge 12.00 cm)
(Width (front/back) with trimming edge 12.50 cm)
(Total width without trimming edge 25.92 cm)
(Height without trimming edge 19.00 cm)