GD库是开着的，后来在DEDE官网上找了个解决办法
测试Securimage结果如下
有两项不对或没有
想问下怎么样才能把这两项补上？
不会是重新安装PHP和nginx吧？
Securimage Test Script
This script will test your PHP installation to see if Securimage will run on your server.
GD Support: Yes!
GD Version: bundled (2.0.34 compatible)
imageftbbox function: No
The imageftbbox() function is not included with your gd build. This function is required.
TTF Support (FreeType): No
No FreeType support. You cannot use Securimage 3.0, but can use 2.0 with gd fonts.
JPEG Support: Yes!
PNG Support: Yes!
GIF Read Support: Yes!
GIF Create Support: Yes!
Based on the requirements, you do not have what it takes to run Securimage :(
------解决方案--------------------------------------------------------
上面提示很明显了..
去PHP 中 开启 imageftbbox 以及 TTF Support..