code: function isValidExtension(src){
     var extension = src.split('.').pop();
     var isValid = ENUM_INVALID_EXTENSIONS[extension] === false ? false : true;
     return isValid;
  }
docs: Check if the extension is considered valid
  @param  {String}  src - url of the image
  @return {Boolean}   true if valid, false otherwise
  @api private