Well, thanks for the hint.

But I want to be able to just import for example a A0 sized poster as a PDF in the right dimensions (just setting hight above the ground). Not more, not less.

The script helps with that by using Blender to create a OBJ file from a given JPEG or PDF with the right dimensions.

This is a real advantage if you want to hang several dozend images or are doing walls completely in Inkscape.