def set_resolution(columns, rows, options={})
      @images.each do |img|
        img.set_resolution(columns, rows, options)
      end
    end
def set_resolution(columns, rows, options={})
      @images.each do |img|
        img.set_resolution(columns, rows, options)
      end
    end
Sets the resolution of the associated images. The images will either be
 expanded or cropped depending on whether the specified resolution is
 bigger or smaller than the existing one.

 @param [Integer] columns the number of columns in the resized images
 @param [Integer] rows the number of rows in the resized images
 @param [Hash] options the options to use for changing the image resolution
 @option options [Float] :hor the side (in the horisontal image direction) at which to apply the crop/border operation (:left, :right or :even (default))
 @option options [Float] :ver the side (in the vertical image direction) at which to apply the crop/border operation (:bottom, :top or :even (default))