If you're trying to use the new <NuxtImg> component with the prismic provider, the unsplash images (used as mock data in slice simulator, but also as an option from slice machine) won't show. This is because they're being optimised as if they were on the Prismic CDN.
Correct me if I'm mistaken, but the <prismic-image> solution doesn't support responsive sizes nor automatic placeholder images (blurhash/LQIP). I was looking at Nuxt/Image to use these features.