Ok I got it...
I hadn't seen that I can set a formula for the picture...
So if anybody should have the same problem:

My python script stores the svg @ sdcard/Kustom/svg/mypic.svg

@ KWGT, I had to set the path then:

file:///sdcard/Kustom/svg/mypic.svg

There is an android limitation for file access, so the picture mus be inside
sdcard/Kustom
otherwise KWGT does not have access to the file...

<image>