pngquantコマンドでほぼ無損圧縮PNGピクチャサイズを70%程度削減

1.インストール
wget http://pngquant.org/pngquant-2.8.2-src.tar.gz
tar -xzf pngquant-2.8.2-src.tar.gz
cd pngquant-2.8.2
インストール依存:yum install libpng-devel
./configure 
make && make install
OK、インストール完了. 
pngquant-h正常かどうか見て、新聞:pngquant:error while loading shared libraries:liblcms 2.so.2:cannot open shared object file:No such file or directory
liblcms 2を取り付け直して、 yum install http://pkgrepo.linuxtech.net/el6/release/x86_64/liblcms2-2.4-1.el6.x86_64.rpm解決
Options
See  pngquant -h  for full list of options. --ext new.png
Set custom extension for output filename. By default  -or8.png  or  -fs8.png  is used. --quality min-max
Instructs  pngquant  to use the least amount of colors required to meet or exceed the max quality. If conversion results in quality below the min quality the image won't be saved (if outputting to stdout, 24-bit original will be output) and  pngquant  will exit with status code 99. min and  max are numbers in range 0 (worst) to 100 (perfect), similar to  JPEG.
 

pngquant --quality=65-80 image.png

--speed N ,  -sN
Speed/quality trade-off from 1 (brute-force) to 10 (fastest). The default is 3. Speed 10 has 5% lower quality, but is 8 times faster than the default. --iebug
Workaround for IE6, which only displays fully opaque pixels.  pngquant  will make almost-opaque pixels fully opaque and will avoid creating new transparent colors. --version
Print version information to stdout. -
Read image from stdin and send result to stdout. --
Stops processing of arguments. This allows use of file names that start with  - . If you're using  pngquant  in a script, it's advisable to put this before file names:

pngquant $OPTIONS -- "$FILE"