add webp image format for preview

@@ -1930,7 +1930,7 @@ jQuery(document).ready(function(){
 
 
     // DRAG and DROP file
-    var available_file_type = ['image/jpeg', 'image/pjpeg', 'image/png', 'image/gif'];
+    var available_file_type = ['image/jpeg', 'image/pjpeg', 'image/png', 'image/gif', 'image/webp'];
 
     var initImageDragDrop = function(){
       $('.drop-down-upload').each(function(){

@@ -466,7 +466,7 @@
     };
     defaultFileTypeSettings = {
         image: function (vType, vName) {
-            return compare(vType, 'image.*') || compare(vName, /\.(gif|png|jpe?g)$/i);
+            return compare(vType, 'image.*') || compare(vName, /\.(webp|gif|png|jpe?g)$/i);
         },
         html: function (vType, vName) {
             return compare(vType, 'text/html') || compare(vName, /\.(htm|html)$/i);

@@ -25,7 +25,7 @@ module Kanjai
 
     def self.image?(url)
       ext = File.extname(url)
-      ['.jpg', '.gif', '.jpeg', '.png', '.svg'].include?(ext)
+      ['.jpg', '.gif', '.jpeg', '.png', '.svg', '.webp'].include?(ext)
     end
 
   end

 module Kanjai
-  VERSION = "0.0.377"
+  VERSION = "0.0.378"
 end