Why does this self closing tag not work?

1. 2020-12-09 at 1:39 AM UTC

   #1
   

   BeeReBuddy motherfucker [pimp your due marabout]
   <img src="https://upload.wikimedia.org/wikipedia/en/9/99/Itispat.jpg" />
   I just wanna know why this isn't a self closing tag?
2. 2020-12-21 at 3:33 AM UTC

   #2
   

   Lanny Bird of Courage
   Because that’s HTML or some other SGML. The forum recognizes a dialect of bbcode, which isn’t the same thing