diff --git a/src/main/java/net/sourceforge/plantuml/servlet/ProxyServlet.java b/src/main/java/net/sourceforge/plantuml/servlet/ProxyServlet.java
index fda09aa..6761209 100644
--- a/src/main/java/net/sourceforge/plantuml/servlet/ProxyServlet.java
+++ b/src/main/java/net/sourceforge/plantuml/servlet/ProxyServlet.java
@@ -61,6 +61,7 @@ public class ProxyServlet extends HttpServlet {
     @Override
     public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
 
+        final String fmt = request.getParameter("format");
         final String source = request.getParameter("src");
         final String index = request.getParameter("idx");
         final URL srcUrl;
@@ -72,6 +73,10 @@ public class ProxyServlet extends HttpServlet {
             return;
         }
 
+        if (fmt != "") {
+            format = fmt;
+        }
+
         // generate the response
         String diagmarkup = getSource(srcUrl);
         System.out.println("getSource=>" + diagmarkup);