image_to_svg = (img) => {
var polygon_points = getImageOutline(img);
var w = d3.max(polygon_points, (d) => d.x);
var h = d3.max(polygon_points, (d) => d.y);
var first_point = polygon_points[0];
var last_point = polygon_points[polygon_points.length - 1];
return html`<svg viewbox="0 0 ${w} ${h}" width="300">
<path d="M ${first_point.x} ${first_point.y}
${polygon_points.map((p) => ` L ${p.x} ${p.y}`)}
L ${last_point.x} ${last_point.y}"/>
</svg>`;
}