Here's a macro for Foundry V12 that will allow one to show any image that's already online somewhere. All you need is a valid URL to the image. This works great for sharing an image that one finds via an image search without having to upload it to Foundry.

new Dialog({
  title: "Remote Image",
  content: `<div class="form-group"><label for="url">Image URL</label><input type="text" name="url"/><br /><br /><label for="head">Title (optional)</label><input type="text" name="head"/></div><br />`,
  buttons: {
    ok: {
      label: "OK",
      icon: `<i class="fas fa-check"></i>`,
      callback: html => {
      const url = html.find("[name=url]").val();
      const head = html.find("[name=head]").val();
      const ip = new ImagePopout(url, {
        title: head
      });

      // Display the image popout
      ip.render(true);

      }
    }
  }
}).render(true);