an example of how attachments work in SMF
click on the image to view a larger size
and click on the name of the file to download the image.

Picture attachment example
logo-hires.png (262.14 KB. 505x505 - viewed 294 times.)
you can attach an image in the middle of the post by using the code:
[ attachment=# ]
Where # is the number of the attachment, Or there is a link next to the attachment to automatically insert the code for you.