Insert the picture URL iside image tags threedog.
[img.]http://www.imageurl.com[/img.]
Remove dots.
Or use the insert image icon in the advanced editor by enabling it in your control panel. (Picture with little green+ on it)
(UserCP / Edit Options / then scroll down to the bottom / Miscellaneous Options / Enhanced Interface WYSIWYG Editing / Save Changes)
Let me know if you have any problems threedog.