new mobile detection code for image iframe

Author: felliott

mfr/extensions/image/templates/viewer.mako

@@ -52,8 +52,7 @@
 
     $(document).ready(function() {
 
-        ## Reference on how mobile is detected: https://stackoverflow.com/a/10364620
-        var isMobile = window.matchMedia("only screen and (max-width: 760px)");
+        var isMobile = window.innerWidth <= 768;
 
         ## Enable the zoom feature only for desktop browsers
         if (!isMobile.matches) {