I’m fine with this. Instances shouldn’t proxy or cache images because it opens instance owners to a lot more liability than text. A client side setting to not load images in comments by default is better.

I store my clothes in a stack, and I usually wear the same few pieces until the season changes.

What you’re describing is no longer federation but full P2P. From a purely technical point of view, it may work, but the biggest problem will be abuse (spam, excessive resource use, illegal content). When a new instance shows up, how do you know if it’s a spammer or not? And if an instance is blocked by another instance, whose side should you be on?