Clicking the insert/edit image button brings up the dialog window with the image URL and description fields.
I input the following url to add an image:
https://cdn.geekzone.co.nz/imagessubs/blogfb00484aea5abe979ae0f3e6f8a6ba15.jpg
and then a broken file icon is shown in the editing pane, with no image.

No matter how ard I try I can't get a second entry in competitions..! what am I doing wrong?