Problem with 3rd party services for images in general is they come and go and delete content and break links or put pay walls up, it's a reoccurring theme over time. So on the forum as a whole, best to host files locally if at all possible and if bandwidth gets out of control use a caching service.
There are some downsides to self hosting images but all manageable. Hosting storage costs are also improving, most customers pay for storage they never use and that is sold on and on to other customers. So it's factored into the cost and a lot has changed since the dedicated disk days.
As much as I like stories, it's unlikely Dave would be held liable for content exchanged between two people in a private context. But you don't want to encourage file sharing, so it makes sense to limit that.