Remove .ashx extension in URLs for Media Items in Sitecore and use real type extension for media items (ie. JPG, GIF, etc.)

      <!--  MEDIA - REQUEST EXTENSION
            The extension to use in media request URLs.
            If the value is not set, the Extension field of the individual media items will be used (ie. JPG, GIF, etc.)
            Default value: "ashx"
      -->
      <setting name="Media.RequestExtension" value="" />