So just confirming that that code lets a user "attach" a file (photo) and then it converts that photo and displays it within the post? 

Is there an option to set to allow more than 1 upload to a post?

Robert, I put the code in the active theme functions.php file and am still just getting a link and not a picture. My site is www.centraloregonlandcruisers.com/forum and I have attached a screen shot. Just wondering what I might still be doing wrong.

You did something wrong. Maybe the functions.php is not the correct file or maybe you inserted in wrong place, e.g. in some other function or out of PHP zone. Please show some screenshot of your functions.php file. Also please clear all caches.

Attached is a screenshot of the .php file

This is not the right place, I meant the WordPress active theme functions.php file not wpForo. Please delete it and move to WordPress active theme functions.php file