@page {
  size: A4;
  margin: 0;
}

@media print {

  body {
    visibility: hidden;
  }

  /* conteneur A4 */
  #print-image {
    display: flex;
    visibility: visible;

    position: fixed;
    top: 0;
    left: 0;

    width: 210mm;
    height: 297mm;

    align-items: center;
    justify-content: center;
  }

  /* image parfaitement contenue */
  #print-image img {
    max-width: 100%;
    max-height: 100%;
    width: auto;
    height: auto;
  }
}