Hello Ivo,
I have run in to an issue that I have reproduced on 2 different sites now. Whenever I have a site where I am using the Slideshow particle and I use the "
LLFJ - Lazy Load for Joomla!" plugin the Slideshow doesn't work properly in that the pictures are not visible in the Slideshow. Once I disable LLFJ the slideshow pictures begin working again.
Can you look in to this for me and let me know if this is something with your particle or if it is an issue with the plugin.
kind regards