php convert jpeg サンプル
http://stackoverflow.com/questions/1201798/use-php-to-convert-png-to-jpg-with-compression
http://qiita.com/Erlkonig/items/ca4dc7d1f8e804011c1f
http://blog.shuffleee.com/1772/
http://memo.ark-under.net/memo/1017
http://jp2.php.net/manual/ja/book.imagick.php
http://fakelife.info/2007/11/09_000054.html
https://github.com/claviska/SimpleImage
http://stackoverflow.com/questions/6610739/php-imagick-convert-png-to-jpg