How can we make simple relative image refs work?

[dannystaple]

Currently, if an image ref is simply relative (and not absolute with respect to content folder), it will not be uploaded to the right place in the site to work.

The img responsive tag, or an absolute content ref will work.

Find a way to make this work with a simple ref and eleventy, while remaining backward compatible with the existing images.

[dannystaple]

This will mean previews in markdown editing tools work correctly, and make posts easier to write.

[dannystaple]

This may be a separate ticket, but Thumbnails should work this way too.