To add links to images once the file has been fully marked up, you have to add code manually. The basic block looks like this:
<p>
<img class="docImageCentre"
src="../../images/site/165643_2.jpg"
alt=""
onclick="openWindow('../../images/site/165643_3.jpg', '../../'); return false;" />
</p>
In some cases the first part of the path is "../../", in others it is "../" and in others an html comment containing the string " rootpath " appears instead. Amanuel's code must process that placeholder, though sometimes it seems to get it wrong. I'll try hardcoding the right path and using the placeholder.

Also turns out that you can "assign" an image to a page. I think that makes the image appear at the top of the page with a full caption. You can't assign an image and have a link to the same image on the page, apparently.

Spent the best part of the day making changes and regenerating the vinland site to see if the changes worked. Should be able to finish up by mid-day tomorrow.