Some images are missing in the export folder. In Blocs it looks fine but in the exported img folder the image file are missing.
I have actualy two pages with this problem. Very strange is that on one page I found a workaround. I create a hidden dupplicate of the image and then it works. But on the other page it doesn‘t.
I’d resave it, call it something different making sure there are no odd characters in the name, make sure it’s RGB format, re-import into Blocs, turn off WebP in your export settings and go from there.