.site-header .navbar-brand .logo {
  width: 100px;
  height: 25px;
  background: url(../images/logo.png) no-repeat;
}
  
@media (min-width: 768px) {
  .compact-sidebar .site-header .navbar-brand .logo {
    width: 25px;
    background: url(../images/logo-small.png) no-repeat;
  }
}

.skin-3 .site-header .navbar-brand .logo {
  background: url(../images/logo.png) no-repeat;
}