The problem is http://lorempixel.com is currently down, and Faker uses this lorempixel site to generate the images.
Unfortunately, this is not configurable from outside the package, but you could find the vendor/fzaninotto/faker/src/providers\Image.php and change the $baseUrl property to something with a similar public API which does work, e.g. https://picsum.photos:
$baseUrl = "https://picsum.photos/";
Going into the vendor directory is normally something I would not recommend, but since this is for local development only, it should be fine. Caveat, I don't know that the Picsum API is 100% consistent with LoremPixel, so you might get some errors.