I haven’t heard that and I’m very much against that if true. Do you have a note you can share that references this?
Discussion
nostr:npub1m4ny6hjqzepn4rxknuq94c2gpqzr29ufkkw7ttcxyak7v43n6vvsajc2jl nostr:note1aqztmcwv5nc2d9sv78emw289f7ykv32kyzj3xfmvwkmz05trv7aqt28ja9
Can confirm. If you go to Primal's web app and look at any image, it is assigned a Primal proxy URL. For example, look at this note from nostr:
On primal, the image URL begins with `r2.primal.net/cache/b/c0/6b/`, but Jumble.social correctly shows that the image is actually hosted on nostr.build.
*...note from nostr:npub10wv37amdqnv8edw5yktgsxr62g8k4lqkk2u66fk6c6uwuakzssxsf4v22x."
Hmm… don’t love that. Just checked on iOS though and I’m able to copy the raw json event as well as the img url which points to Nostr.build. I’ll try on my pixel and on the web app later on. Thanks for sharing that

There's still something funky happening with the mobile app, too. For instance, this note shows tje image has been removed from nostr.build on most clients, but it is still visible on Primal's app, until you tap to view it full screen.
Primal screenshot:

Expanded:

This suggests that primal is showing their cached version until you open the image, rather than just showing the original.
I deleted the image from nostr.build
Now, bear in mind, Primal is not the only Nostr app that does this. Coracle I would definitely classify as a Nostr client, yet it also uses an image proxy, which I assume is why media sometimes takes so long to load on Coracle.
For instance, the same note from nostr:npub10wv37amdqnv8edw5yktgsxr62g8k4lqkk2u66fk6c6uwuakzssxsf4v22x on Coracle loads the image URL starting with `imgproxy.coracle.social/x/s:640:1024/"