<% Image.show %>
render the image-tag (link to main action if image is a thumbnail)

Sourcecode in Image/macros.js:
1:   function show_macro(param) {
2:      var img = this;
3:      // if we have a thumbnail, display that
4:      if (param.as == "thumbnail" && this.thumbnail) {
5:         var url = this.href();
6:         img = this.thumbnail;
7:      } else
8:         var url = img.getUrl();
9:      delete(param.what);
10:     param.src = img.getUrl();
11:     Html.openLink({href: url});
12:     renderImage(img, param);
13:     Html.closeLink();
14:     return;
15:  }