_config.PHP

Object::add_extension('Image','Greyscaled');

更新：从SilverStripe 3.1开始,您应该使用配置系统而不是_config.PHP.将以下内容放在你的mysite / _config / config.yML中(不要忘记？flush = 1以在添加后重新加载配置缓存)：

Image:
  extensions:
    - 'Greyscaled'

Greyscaled.PHP

<?PHP
class Greyscaled extends DataExtension {
    //This allows the template to pick up "Greyscaleimage" PRoperty,it requests a copy of the image From the cache or if it doesn't exist,generates a new one
    public function GreyscaleImage($RGB = '76 147 29') {
        return $this->owner->getFormattedImage('GreyscaleImage',$RGB);
    }

    //This is called internally by "generateFormattedImage" when the item is not already cached
    public function generateGreyscaleImage(GD $gd,$RGB) {
        $VARs = explode(' ',$RGB);
        return $gd->greyscale($Vars[0],$Vars[1],$Vars[2]);
    }
}

UPDATE2：3.1的更新版本？您可以传递2个以上的参数,GD已重命名为Image_Backend.这样,图像名称中的RGB值之间就没有空格.请注意$gd-> greyscale需要很多果汁 – 所以你可能会先缩小尺寸,然后再使用GreyscaleImage.

更新3：由于这个答案最近获得了一些投票,我认为人们仍在使用它,但我认为在2017年CSS过滤器在许多情况下是更好的选择.有前缀你将有近90％的覆盖率.
css-filters on caniuse.com

<?PHP
class Greyscaled extends DataExtension {
    public function GreyscaleImage($R = '76',$G = '147',$B = '29') {
        return $this->owner->getFormattedImage('GreyscaleImage',$R,$G,$B);
    }
    public function generateGreyscaleImage(Image_Backend $gd,$B) {
        return $gd->greyscale($R,$B);
    }
}

并在模板中：

<img src="$Images.GreyscaleImage.CroppedImage(1000,400).URL" alt="$Images.Title" />

Silverstripe 3.1 Image API