Ok, let's go step by step.
First of all, you should upload your photo to a hosting service of your choice. I use Flickr, and one of my pictures can be seen on the following page:
That's called a URL (the "http://www...").
Note that the URL is not of the photo itself (it doesn't end with ".jpg"), so we'll need to use this instead:
http://farm3.static.flickr.com/2021/160 ... 1591f4.jpg
Now, how do I make that photo appear here?
I wrap some tags around the URL, like this:
Notice the "[img]...[/img]" tags. That's what will make the photo appear.
So now we can see it like this:
Try this with one of your photos, and then we'll try to add a link to it (so that others can click on it and see the original).
I hope this helps.