papercss/src/content/_images.scss

img {
  @include border-style();
  border: 2px solid $primary;
  display: block;
  height: auto;
  max-width: 100%;

  &.float-left {
    float: left;
    margin: 1rem 1rem 1rem 0;
  }

  &.float-right {
    float: right;
    margin: 1rem 0 1rem 1rem;
  }

  &.no-responsive {
    display: initial;
    height: initial;
    max-width: initial;
  }

  &.no-border {
    border: 0;
    border-radius: 0;
  }
}