コマンドラインでwgetとconvertを同時に使う

$ wget -q -O - http://www.google.co.jp/intl/ja/images/google_sm.gif | convert -quality 30 -resize 200x200 - jpeg:- > a.jpg

これで良い。

さらにパイプに回してMIMEエンコードできる。

$ wget -q -O - http://www.google.co.jp/intl/ja/images/google_sm.gif | convert -quality 30 -resize 200x200 - jpeg:- | ruby -e 'puts [STDIN.read].pack("m")'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