There had been a poll with this in mind, to have images on a third party platform, but it had it's problems, while this DOES give a specifc third party, it's unlikely to get approved of. For the previous poll here is a link https://www.worldanvil.com/community/voting/suggestion/83866095-d725-46b6-8a0f-52e7882fc561/view
I agree with previous comments. This seems like potential for issues and it's such a minor gain, that I'd rather see development time to go into other things.
Nope, I see so many issues with this. I do not like this idea at all.
I have a Dropbox account and I get that images can be held remotely without local copies, but any file on Dropbox can be quickly and easily downloaded locally and after that it is trivial to post it to WA, so I'm not entirely clear on why this is such a necessary requirement. I can also see it being a complex nightmare of security issues to implement. I feel the OP has to make a better case for why this is so desirable before I'd support time and effort being spent on it.