CSS force image resize and keep aspect ratio

Question

I am working with images, and I ran across a problem with aspect ratios.

Answer 1

How about using a pseudo element for vertical alignment? This less code is for a carousel but i guess it works on every fixed size container. It will keep the aspect ratio and insert @gray-dark bars on top/bottom or left/write for the shortest dimension. In the meanwhile the image is centered horizontally by the text-align and vertically by the pseudo element.

    > li {
      float: left;
      overflow: hidden;
      background-color: @gray-dark;
      text-align: center;

      > a img,
      > img {
        display: inline-block;
        max-height: 100%;
        max-width: 100%;
        width: auto;
        height: auto;
        margin: auto;
        text-align: center;
      }

      // Add pseudo element for vertical alignment of inline (img)
      &:before {
        content: "";
        height: 100%;
        display: inline-block;
        vertical-align: middle;
      }
    }