I am writing this because many people are finding it difficult to find the attachments tab while writing a forum post.
Images can be uploaded only through the attachments tab.
Please note that the attachments tab for images is only found in the full edit page of a post.
U will have to click on "More Options" below a quick edit post to open the full post editor.
U will see the attachments tab at the bottom of the full edit page next to the smileys.