For those migrating to Radiant CMS 1.0 who used Paperclipped Extension, here's rake task to migrate images from the Paperclipped folder structure to the new Clipped extension folder structure.

migrate_clipped.rake

require 'fileutils'

    namespace :clipped do

    desc "Migrate assets from Paperclipped to Clipped"
    task :migrate => [:environment] do
      skippable_entries = [".", "..", ".DS_Store"]
      new_assets_dir = "public/system/assets"
      dir = Dir.new("public/assets")
      dir.entries.each do |entry|
        next if skippable_entries.include?(entry)
        FileUtils.mkdir("#{new_assets_dir}/#{entry}") unless File.directory?("#{new_assets_dir}/#{entry}")
        Dir.new("#{dir.path}/#{entry}").entries.each do |asset|
          next if skippable_entries.include?(asset)
          puts "Copying #{dir.path}/#{entry}/#{asset}"
          if asset.include?("_thumbnail.")
            FileUtils.mkdir("#{new_assets_dir}/#{entry}/thumbnail") unless File.directory?("#{new_assets_dir}/#{entry}/thumbnail")
            FileUtils.copy("#{dir.path}/#{entry}/#{asset}","#{new_assets_dir}/#{entry}/thumbnail/")
          elsif asset.include?("_icon.")
            FileUtils.mkdir("#{new_assets_dir}/#{entry}/icon") unless File.directory?("#{new_assets_dir}/#{entry}/icon")
            FileUtils.copy("#{dir.path}/#{entry}/#{asset}","#{new_assets_dir}/#{entry}/icon/")
          elsif asset.include?("_normal.")
            FileUtils.mkdir("#{new_assets_dir}/#{entry}/normal") unless File.directory?("#{new_assets_dir}/#{entry}/normal")
            FileUtils.copy("#{dir.path}/#{entry}/#{asset}","#{new_assets_dir}/#{entry}/normal/")
          else
            FileUtils.mkdir("#{new_assets_dir}/#{entry}/original") unless File.directory?("#{new_assets_dir}/#{entry}/original")
            FileUtils.copy("#{dir.path}/#{entry}/#{asset}","#{new_assets_dir}/#{entry}/original/")

            ext = File.extname(asset)
            asset_without_ext = asset.gsub(ext, "")
            FileUtils.mkdir("#{new_assets_dir}/#{entry}/native") unless File.directory?("#{new_assets_dir}/#{entry}/native")
            FileUtils.copy("#{dir.path}/#{entry}/#{asset}","#{new_assets_dir}/#{entry}/native/#{asset_without_ext}_native#{ext}")
          end
        end
      end
  end
end