.picturepanel {
  width: -webkit-fit-content;
  width: -moz-fit-content;
  width: -ms-fit-content;
  width: fit-content;
  max-width: 500px;
  max-height: 300px;
  border: 2px solid silver;
  overflow: auto;
  position: relative;
}
.picturepanel canvas { display: block; }
.toolbar > * { margin-right: 5px; }