Update custom.html

apps/openseachart/custom.html

@@ -199,7 +199,7 @@ TODO:
                     resolve();
                   };
                 }));
-                img.src = 'http://sandshore.duckdns.org:2552/boca_ciega_cr.png';
+                img.src = 'https://raw.githubusercontent.com/berkenbu/BangleApps/master/apps/openseachart/boca_ciega_cr.png';
               })(i,j);
             }
         }