The foolproof way to add a picture to a post (if you're in IE):

1. Attach it as you would do normally.
2. Go back to your post.
3. Right click on the 'Attachment' link and hit 'Properties'. Copy all of the text from the 'Address' field into the clipboard.
4. Back at your post, hit Edit.
5. Put the following text: [ image ] [ /image ] (without any spaces) in your text, and paste the link in between the two tags.
6. Uncheck the 'mark as edited' box.
7. Save changes.