如果webmin/virtualmin上传图片，出现如下错误，说明gd库可能没有启动。webmin上传图片报错，如何安装gd库？：

[error] [client 127.0.0.1] PHP Warning:  imagecreatefromstring() [<a href='function.imagecreatefromstring'>function.imagecreatefromstring</a>]: Data is not in a recognized format in /www/host/www.ctohome.com/hbcms/include/pear/Image/Tools.php on line 558, referer: http://www.ctohome.com/hbcms/user/add_resource.php
 

首先确认有gd.so文件

[[email protected] ~]# ls /usr/lib/php/modules/
curl.so   gd.so    json.so      mysqli.so  odbc.so       pdo_odbc.so   pdo.so         pgsql.so    snmp.so    zip.so
dbase.so  imap.so  mbstring.so  mysql.so   pdo_mysql.so  pdo_pgsql.so  pdo_sqlite.so  phpcups.so  xmlrpc.so

然后vi /etc/php.ini 确定有下面一行，如果没有，添加

extension=gd.so

重启apache

service httpd restart