MediaWiki:Chat.css

#WikiChatList li[data-user="Niko-Zero-Havik Neck"] {
	background-image: url("http://i.imgur.com/ZksWFwa.png");
}
#WikiChatList li[data-user="Rodrigo fraysse"] {
	background-image: url("http://www.subeimagenes.com/img/kitana-banner-612x252-1556157.png");
}
#WikiChatList li[data-user="Sasuke2004"] {
	background-image: url("http://www.subeimagenes.com/img/banner-for-batman-on-wenoo-by-pokedudeavenger-d6by-1556164.png");
}

.User.chat-mod .username:after {
    content: url("http://static3.wikia.nocookie.net/__cb20131114165428/mortal-kombat-fanon/es/images/6/64/Favicon.ico") !important;
}
/* Parte interior del Chat */
body.ChatWindow { background: url("http://www.videogamesblogger.com/wp-content/uploads/2011/04/mortal-kombat-2011-cast-wallpaper-by_sakis25.jpg") repeat scroll center top black;
text-shadow: 1px 1px 1px black; background-attachment:fixed; background-size: 1024px 600px; color:white; } /* Parte exterior del chat */ body.ChatWindow .WikiaPage { background: url("http://www.videogamesblogger.com/wp-content/uploads/2011/04/mortal-kombat-2011-cast-wallpaper-by_sakis25.jpg") repeat scroll center top black; /* Aqui tienes que hacer lo mismo que arriba y poner la URL de la misma imagen, a menos que quieras poner otra imagen */ text-shadow: 1px 1px 1px black; border: 1px solid #8A2BE2; background-attachment:fixed; background-size: 1024px 600px; color:white; }