Finally, last night, the Insert penny dropped! To get images inline two conditions need to be met:
- the Content Type must have a File Upload field included at Home > Structure > Content types > Travel > Manage fields. The example here is the Travel Content type where the label is Add Image.
- At the bottom of the Travel settings is (contracted) the Insert control. Expand it and tick the Enable insert button box.
Then a couple of hours of fiddling determined how to hide the Add Image file attachment when viewing. How to pick an image style for the insertion. Now I think I need to learn how to configure styles so that a thumbnail is positioned as desired and is enlarged in Colorbox when tapped.