Images relative paths should be substituted for absolute URL

[truenicoco]

If I attach an image to a page, eg ![caption](image.png), in the entry/content XML it will be <img src="image.png" alt="caption">, which does not let feed reader retrieve the image at the right URL.

[dancergraham]

+1 for this - it would be nice to include images in the feed

Here is an example with absolute urls for the blog items but broken relative urls for the images https://grahamknapp.com/feed.xml