If you look at the source code you can see this:
<img data-lazy="https://www.farmaciacormanas.com/3744-home_default/bioderma-hydrabio-serum-40ml.jpg" alt="BIODERMA HYDRABIO SERUM 40ML" data-full-size-image-url="https://www.farmaciacormanas.com/3744-thickbox_default/bioderma-hydrabio-serum-40ml.jpg" width="236" height="305" class="img-fluid product-thumbnail-first">
The code needs this to see the image:
src="https://www.farmaciacormanas.com/3744-home_default/bioderma-hydrabio-serum-40ml.jpg"
I've tried to reinstall the cross selling module but it doesn't fix the issue.
Anyway, the missing images are not only at the cross selling module. They are missing in all the modules with carrousels...
Any help will be apreciated!!!