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:
nostr:nevent1qvzqqqqqqypzq7ueramk6pxc0j6agfvk3qv855s0dt7pdv4e45nd434caemv9pqdqqswfq02ghfjxu4hhcjfa3qlrrqad9xaujdrdxw2c5mlgxwx2vaj87cu9mxe8
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.
