The picture has to be some where on the internet. Copy the link. Then type [img] paste the link, then close it with [/img]
Since you have them uploaded you can copy the link in your post and paste it in the insert image pop up on the post tool bar. Just remember to delete the http:/ that the pop up automaticaly adds
. The link will have its own http:/ in the address and will cause an error if there are two.