Yes the ad blockers prevent loading of many images. I use Libreworlf as a browser and I don't see many images from profiles because they are simply blocked by the browser itself because the urls don't meet privacy standards. This will probably always be a problem when using urls on external hosts.
Discussion
I leave most of my ad blocking up to my pihole so I can have more granular control over it. This is actually the first instance that I've noticed of the pihole blocking images from loading on nostr, that's why it threw me off.
This is because no image proxy is used yet either. I have put it on the roadmap. These are the original image urls of the profiles. And there is a lot that can go wrong with that.