hoehnp In my case it seems to be the opposite. I see the images properly in Sozi.
It reminds me of this other issue.
The images were visible in Sozi but not in the web browser when playing the presentation.
The images became visible when I removed other, seemingly unrelated, elements from the SVG.
The issue is closed because the original poster never replied to my requests for information. But it is not solved yet. The provided example was too complex to be usable in my investigations.
hoehnp Do you want me to send you my file?
In all my tests, embedded images are always rendered correctly. I need to see a non-working document to understand the problem.
If you agree to send me your files, I suggest to use a file sharing service like Framadrop. You can either share a link to the files publicly in this conversation, or send it to me privately by e-mail (sozi at baierouge dot fr)