Attach the picture to the post using the attachments button.
submit the post.
When the post comes back up open the attachment.
Copy the address of the attachment from the address bar.
Go back to your post and edit it by selecting options\edit post.
Go to the place in your post where you want the PIC to be and hit the insert an image button on the editor menu bar (the one that looks like a picture).
paste the address that you copied into the dialog that appears and hit ok.