It works with remotely-hosted photos, like those on Flickr or other hosting services.
Get the direct link to the photo itself (not the page it’s on) and copy it to your clipboard. Then click the “img” button in the reply editor. A tiny window pops up and you paste your link. Say OK and you end up with something like this in the editor:
<img src="https://c7.staticflickr.com/9/8759/28172773702_39cec2bea8_c.jpg" alt="" />
At the moment, I see no way to preview your post, so you’ll just have to pray that it works. Although I believe that there is an edit option after you post.
San Gorgonio and the nine peaks from the PCT north of Big Bear Lake, Memorial Day Weekend 2016. Yes, there was still snow up there…