.jumbotron {
  background: url('/assets/img/jumbotron.png') no-repeat left top;
  background-size: 100%;
  color: $white;
  height: 656px;
  padding-top: 200px;
  position: relative;
  text-align: center;

  h1 {
    font-size: 54px;
    font-weight: 700;
  }

  .lead {
    font-size: 24px;
    height: 1.8em;
  }

  .arrow-down {
    bottom: 50px;
    color: $white;
    left: 50%;
    position: absolute;
    transform: translateX(-50%);
    transition: bottom .3s;

    .fa {
      text-shadow: 2px 0 4px 0 fade-out($black, .5);
    }

    &:hover {
      bottom: 55px;
      transition: bottom .3s;
    }
  }
}

.navbar {
  font-family: $font-family-sans-serif;
}

.jumbotron {
  background: url('/assets/img/jumbotron.jpg') no-repeat left top;
  background-size: cover;
  color: $white;
  height: 450px;
  padding-top: 120px;
  position: relative;
  text-align: center;

  @include media-breakpoint-up(sm) {
    h1 {
      font-size: 54px;
      font-weight: 700;
    }

    .lead {
      font-size: 24px;
      height: 1.8em;
    }
  }

  &.short {
    height: 250px;
  }

  h1 {
    font-weight: 700;
  }

  .arrow-down {
    bottom: 50px;
    color: $white;
    left: 50%;
    position: absolute;
    transform: translateX(-50%);
    transition: bottom .3s;

    .fa {
      text-shadow: 2px 0 4px 0 fade-out($black, .5);
    }

    &:hover {
      bottom: 55px;
      transition: bottom .3s;
    }
  }
}

.navbar {
  font-family: $font-family-sans-serif;
  position: absolute !important;
}

Change jumbotron img url and size
Change jumbotron img url and size
