I suggest taking a look at your html sanitization settings make sure html isn't allowed in markdown settings.
Next step would be to move the other 2 topics from that category and check if you still see broken markup.
[url=http://valid.x86.fr/m6vn6f][img]http://valid.x86.fr/cache/banner/m6vn6f-5.png[/img][/url] this is not working...jsut shows that string
@Ryan-Oliver don't think signature supports images
or well it should be more of how do I post a banner in my sig, not image
@Ryan-Oliver speaking of signature I don't see the option to add/change signature in persona
[![CPU-Z] "" (http://valid.x86.fr/cache/banner/m6vn6f-5.png)] < No quotes will add banner in signature