code: @Override
  	protected String getContentType(String filePath, HttpServletRequest request) {
  		String requestUri = request.getRequestURI();
  
  		// Retrieve the extension
  		String extension = getExtension(filePath);
  		if (extension == null) {
  
  			LOGGER.info("No extension found for the request URI : " + requestUri);
  			return null;
  		}
  
  		String binContentType = (String) binaryMimeTypeMap.get(extension);
  		if (binContentType == null) {
  
  			LOGGER.info(
  					"No binary extension match the extension '" + extension + "' for the request URI : " + requestUri);
  			return null;
  		}
  		return binContentType;
  	}
docs: Returns the content type for the image
  
  @param filePath
  the image file path
  @param request
  the request
  @return the content type of the image