（1）先下载好一下几个库
zlib-1.2.8.tar.gz libpng-1.6.18.tar.gz jpegsrc.v9a.tar.gz freetype-2.4.0.tar.gz libgd-2.1.1.tar.gz
文件下载地址自行Google搜索
（2）创建目录，编译安装
先在/usr/local文件夹下面创建好几个目录
mkdir zlib mkdir libpng mkdir libjpeg mkdir freetype mkdir libgd2
编译安装zlib
tar -xzvf zlib-1.2.8.tar.gz cd zlib-1.2.8 ./configure --prefix=/usr/local/zlib make && make install
编译安装libpng
tar -xzvf libpng-1.6.18.tar.gz cd libpng-1.6.18 ./configure --prefix=/usr/local/libpng --enable-shared make && make install
编译安装libjpeg
tar -xzvf jpegsrc.v9a.tar.gz cd jpeg-9a ./configure --prefix=/usr/local/libjpeg --enable-shared make && make install
编译安装freetype
tar -xzvf freetype-2.4.0.tar.gz cd freetype-2.4.0 ./configure --prefix=/usr/local/freetype --enable-shared make && make install
以上都编译安装好后，现在来编译安装gd库
tar -xzvf libgd-2.1.1.tar.gz cd libgd-2.1.1 ./configure --prefix=/usr/local/libgd2 --with-png=/usr/local/libpng --with-jpeg=/usr/local/libjpeg --with-freetype=/usr/local/freetype --with-zlib=/usr/local/zlib make && make install
重新编译PHP
cd php-5.6.14 ./configure --prefix=/usr/local/php --with-mysql=mysqlnd --with-pdo-mysql=mysqlnd --with-pdo-mysql=mysqlnd --with-apxs2=/usr/local/apache2.4/bin/apxs --with-libxml2=/usr/local/libxml2 --with-gd --enable-gd-native-ttf --with-zlib-dir=/usr/local/zlib --with-png --with-jpeg --with-freetype-dir=/usr/local/freetype make & make install
编译完成后，重启apache
/usr/local/apache2.4/bin/apachectl restart Error:……modules/libphp5.so in libpng16.so.16 cannot open shared object file: No such file or directory
这里报了个错误
加个链接后，可以解决这个问题
引用
ln -s /usr/local/libpng/lib/libpng16.so.16 /usr/lib/libpng16.so.16