dataURIを作る ref: http://qiita.com/items/3cd7d6d4c250c382d031

base64_embed_datauri.rb

#!/usr/bin/env ruby

require 'base64'
require 'rubygems'
require 'mime/types'
require 'optparse'

##初期化
with=false
####引数処理
opt = OptionParser.new
opt.on(
	"--tag=[TAG]",
	"タグに埋め込んだ状態で出力する.デフォルト<img>(MIME判別) "){|arg| 
		case arg
			when nil
				with = "img"
			when false
				with = false
			else
				with = arg
		end
	}
	
opt.on("--css", "CSS埋め込み用に展開する .url(\"data:image/png;base64,XXXX\") "){ |arg| with = "css"|| arg  }
opt.parse!(ARGV)

###メイン処理
data_type =  MIME::Types.type_for(ARGF.path).first.to_s
if with != false then
	with = "script" if data_type =~/script/i
	with = "img"    if data_type =~/image/i  and not with=="css"
	#with = "embed"  if data_type =~/flash/i # no browser support swf in data uri scheme
	with = "svg"    if data_type =~/svg/i
end

data_str  =  Base64.encode64(ARGF.read).gsub /\n/,""
src_str =  "data:#{data_type};base64,#{data_str}"

##出力処理
case with
	when "img"
		puts "<img src=\"#{src_str}\" />"
	when "script"
		puts "<script src=\"#{src_str}\"></script>"
	when "css"
		puts "url(\"#{src_str}\""
	when "object"
		puts "<object data='#{src_str}' type='#{data_type}'> </object>"
	when "embed"
		puts "<embed src='#{src_str}' type='#{data_type}' />"
	when false
		puts src_str
	else
		puts "<#{with} src=\"#{src_str}\" />"
end