JohnDuncan:
Right. When you hover over the pic in photobucket, four boxes appear below it, one of which says "direct link" I think. Select the text in that box and copy the link. Then come back here and click on the 'insert image' button.
Paste the link into the 'Image URL' box, and fill in the first 'dimensions' box only with the number 400, deleting the contents of the other box. Click insert and you're done.
Right, I've clicked the text in the box and copied the link. That's fine. I've come back to this site and can't find 'insert image' button. Further directions please.