public string ComposeHtml(Template template, List<ImagePayload> images)
        {
            StringBuilder imageCorpus = new StringBuilder();
            foreach (var image in images) {
                imageCorpus.AppendFormat(template.ImageTemplate, image.Path, image.Caption);
            }

            StringBuilder builder = new StringBuilder();
            builder.AppendFormat(template.BodyTemplate, imageCorpus);

            return builder.ToString();
        }
 public string ComposeHtml(Template template, List<string> imagePaths)
 {
     var payloads = imagePaths.Select(path => new ImagePayload(path, "")).ToList();
     return ComposeHtml(template, payloads);
 }