- Click the post reply button
- Type a message and click Browse to attach your attachment to your post
- Click Post reply to post the message and the attachment
- You will see that the attachment is a link to the file you attached. If this is an image, you can add it into your post. To do that, copy the image location (right click the attachment name (hyperlink) and choose Copy link location or similar option)
- Click the Edit button below your post to edit your post
- Enter a line in your post that says
[img]url[/img]
where url is the url of your attachment (just paste the text you copied)
That should work, good luck