Posting Images?

[Sargassoc]

So I'm trying to post an image. Using the Insert/Edit Image button, I've tried to post a link to a Flickr account (as well as a shared Dropbox link) and also uploaded an image and tried post that way. In the first case, in Preview, I see only a broken link. When I try to post an uploaded image, in Preview I only see the message: View attachment# (where # is the uploaded attachment number).

I've changed browsers, too.

Am I missing something?