Metadata in markdown links?

There is no way to use the variables in your post!

But if you're trying to embed an image within your blog folder, please note you don't need to fully-qualify the URL. For example, this markdown will render correctly given your current directory structure:

![Caption](/_images/picture.jpg)

And this will work too, if _picture.jpg is inside the same directory as the markdown file:

![Caption](_picture.jpg)

Does that help?