/*Фон в привате*/

.chatMain .chatPrivateMessages {
background-image: url("Адрес картинки");
background-position: left top;
background-repeat:no-repeat;
background-size: 100% 100%;

border-image-width: 3px;
border-image-source: url(http://imgs.su/users/70140/1488814776.gif);
border-image-slice: 30;
border-image-repeat: stretch;
box-shadow:  -6px 6px 7px -4px #333;
}

/*Фон правой колонки*/
chatPeople {
background-image: url("http://imgs.su/users/70140/1489680758.jpg ");
background-position: center center;
background-repeat: no-repeat;
background-size: 150% 110%;

border-image-width: 5px;
border-image-source: url(http://imgs.su/users/70140/1488815108.gif);
border-image-slice: 30;
border-image-repeat: stretch;

box-shadow:  -6px 6px 7px -4px #333;
}