Just wrap Image tags around your picture. Example: [IMG] (url) [/IMG]. That should work for you if your URL is correct.
Although Hotlinking is frowned upon and that's what you're suggesting it seems.
Actually no I wasn't so sorry if it sounded that way. It's preferable if your images are in, say, your own personal Photobucket account so they're not Hotlinked from another website without that site's permission. My suggestion? Copy an image, transfer it to your own site or online photo account and then employ the Image tags.
There. I'm not a tech guy so my explanations sometimes leave something to be desired. My bad.