garments_controller.rb

  def new 
    @garment = Garment.new(params[:id])
    @garment.save

    if ImageSaver.new(@garment).save_garment_with_image
      respond_to do |format|
        format.html
      end 
    end 
  end 

end

image_save_service.rb

class ImageSaverService

  def inititalize(garment)
    @garment = garment
  end 

  def save_garment_with_image
    if url_has_changed
      do_the_savey_thing
      @garment.save
    else
      do_the_other_thing
    end 
    @garment
  end 

end