ImageScience.with_image(staging_filename) do |image|
      # sorry about the lambda - IS uses blocks to guarantee that images are
      # freed - and we don't want to resize an image if it's already 600x600
      saver = lambda {|to_save| to_save.save(idea_filename)}
      if image.width == 600 && image.height == 600
        saver.call(image)
      else
        dim = [image.width, image.height].min
        image.resize(dim,dim) {|resized| saver.call(resized) }
      end
    end