resize image using gd2 or generate thumbnail of image

thumbnail.rb

require 'rubygems'
require 'gd2-ffij'
class Thumbnail
  include GD2
  def self.thumb(file_name,thumb_name,resized_width=100,resized_height=100,options={})
    #import image
    image = Image.import(file_name)
    #resize image by passing width and height
    resize_image =  image.resize(resized_width, resized_height,true)
    # export an image to desired file format
    resize_image.export(thumb_name,options)
  end
end

Thumbnail.thumb('test.jpg','thumb1.png',200,300)