gistfile1.rb

def upload_sizing
  result = {}
  size = {:width => self.upload_width, :height => self.upload_height}
  thumb_size = {:width => self.upload_thumb_width, :height => self.upload_thumb_height}
  keys = []
  
  keys.push "resize" if self.enable_images?
  keys.push "encode" if self.enable_videos?
  
  keys.each do |key|
    result[key.to_sym] = size if self.upload_width? && self.upload_height?
    result["#{key}_thumb".to_sym] = thumb_size if self.upload_thumb_width? && self.upload_thumb_height?
  end
  
  result[:export][:use] = result.keys.collect { |key| key.to_s }
  result
end