503 error on new site

Website: https://chrismcb.com
hosted on fastcoment through their ghost publishing platform.
I’m converting the site, and uploaded a bunch of images to content/images by hand
Ghost v 3.41.5
sqlite3 (I wonder if I would be better off with mysql?)
development mode

On the home page, after scrolling a page or two, the site dies with a 503.
Log is IMAGE_PROCESSING “Unable to manipulate image.”
My SUSPICION is that the site is trying to create the resized images, and fails (either because it tried to resize too many at once, or who knows…) But I get the 503 and no the site is dead. I need to restart it.

Is there a way to “seed” the resized images?
Is my suspicion close? Is it possible to catch this error and not crash, and just return a nil image?
I saw someone else is having a similar issue, but there was no response