With some of these links, I could try, if the same problems with bulk import exist on my machine.
You just gave us the three pictures, which I then uploaded on my server. That’s different.
I typically use Affinity Photo or Photoshop, however I do have the basic version of Pixelmator, so I just tried saving those for web usage. They actually appear with no extension in the finder, but after making this visible it appeared as jpg and not jpeg.
I tried with those images and had the same problem, so I tried with some of my own images and now I am having the same problem there as well. This has never occurred before trying your images and I am doing this all the time, so I don’t know what is happening here but they seem to be creating problems for Blocs. Have you sent in a bug report?
But from my very limited experience with using Blocs is(I’m a newbie), if a problem occurs, just quit Blocs, and restart.
I have loaded my project, a few days ago, and a lot of images(nearly half) in asset-manager showed a question-mark. I then force-quitted Blocs 4 times, and then all the images appeared. Display in asset-manager was getting better every time.
Today I opened up my project, and even that asset-manager showed all files, some of the images in my pages showed question-marks and even collapsed. Never saw that . I then quitted and restarted and all was fine…
Trying to use hosted assets as well, it works in general but does not work when I used webp files, even though it says webp is supported. When I add those webp images locally instead, it works seamlessly. Just not when hosted…