I'll explain it to you mumsy.
1st of all, we can't see what's on your hard disk. Only you can. So that's why you see pictures there. IF we could see those pictures, we could also see everything on your computer. you wouldn't like that hey !!!
So, you have to "Upload" your picture(s) to a site, like www.photobucket.com and from there you can link them to here on JWD.
So, you have to go to photobucket and sign up. It,s free. Upload a picture there, and when you see your picture on that site, right click on the picture, and press on "copy", and then come here on JWD and post your picture by pressing on the "paste" icon on top, the second icon to the right of the scissors.
Another way would be to upload your pictures here by clicking on "files" on the top left of the page, right next to where you log in and logoff. When you go into the "files section", you can upload your picture there. Once it's uploaded there, you will see it in that section. Then you can paste that picture for all of us to see it, by clicking on the paper clip you see up there. :)