Dude360 Goto Global Settings>Forum>Wcode>Then untick [img] And Save.. Then enable Wcode By Ticking It And Then Save..
Now, Goto Your Forum Bottom Autocontent and paste this code

<style>.figure { position: relative; max-width: 100%; } figcaption {position: absolute; bottom: 0px; left: 10px; letter-spacing: -1px; color: white; background: rgb(0, 0, 0); background: rgba(0, 0, 0, 0.6); padding: 7px 10px 7px 10px; }</style><div><script language="javascript"> var msg=document.getElementsByName("dpro"); for(var i=0;i<msg.length;i++) { var txt=document.getElementsByName("dpro")[i].innerHTML; txt=txt.replace(/\[img\](.+?)\[\/img\]/ig,'<figure class="figure"><img src="$1" alt="'+document.title+'" style="max-width:100%" class="img-thumbnail" name="imgtop" /><figcaption>YOUR SITE NAME</figcaption></figure>'); document.getElementsByName("dpro")[i].innerHTML=txt; } </script></div>

Goto Your Message In Forum.. Click on d first box and replace ::msg:: with <div name="dpro">::msg::</div>

It Works For Me