I'm trying, and failing, to include images that appear as attachment to blog posts.

I've ported an old blogger blog into my personal confluence installation. Some blog posts have images (Confluence will allow me to more easily add even more) attached.

I'm creating Confluence page's with central themes, eg. a trip to Brasil, that I have several tagged blog posts about.
On this page I want to include all images from these blog posts according to my tags.

I see this exact functionality does not exist according to the documentation
However, I am supposed to be able to add images that appear on a page.

Blog posts apparently are not "pages", so I can't do this. Or, I just don't know how to name a specific blog post so that it can work as I want. I've tried:
No pictures: a blog posts' title, YYYY/MM/DD/Title
Pictures: a page name

I (probably?) replicated the problem in the sandbox, http://sandbox.onconfluence.com/display/ds/gallery+macro+include+blog+attachment+images+bug+test