gistfile1.rb

def upload_sizing
  result = {}
  
  if uploads_enabled?
    dims = lambda {|size| send("upload#{size}_width?") && send("upload#{size}_width?") ?
      { width: send("upload#{size}_width"), height: send("upload#{size}_width") } : nil
    }
    
    {:enable_images? => :resize, :enable_videos? => :encode}.each do |method, result_key|
      ['', '_thumb'].each do |size|
        result["#{result_key}#{size}".to_sym] = dims.call(size) if dims.call(size)
      end if send(method)
    end
  end

  result[:export] = { use: result.stringify_keys.keys }  
  result
end