无法安装 Laravel 包 干预图像

So I am following the tutorial on tuts+ Premium from Jeffrey Way - Creating an Ecommerce App in Laravel 4 and I am stuck with this problem. He is installing a package by just editing the composer.json file with this line "intervention/image": "dev-master" and then just types 'composer update' into his console. I try the same but it won't work.

它会显示这个错误

" Problem 1 - intervention/image 2.0.2 requires ext-fileinfo * -> the requested PHP exte nsion fileinfo is missing from your system. - intervention/image 2.0.1 requires ext-fileinfo * -> the requested PHP exte nsion fileinfo is missing from your system. - intervention/image 2.0.0 requires ext-fileinfo * -> the requested PHP exte nsion fileinfo is missing from your system. - Installation request for intervention/image 2.* -> satisfiable by interven tion/image[2.0.0, 2.0.1, 2.0.2]."

我试着按照他们在http://image.intervention.io/getting_started/installation上的指示操作，但不起作用.

I don't know how to handle this issue. Please help. I also read somewhere that I should edit the php.ini file and uncomment a line for fileinfo but after restarting Apache again it did not work.

我正在使用Windows 8和wamp和Laravel.

Any help would be appreciated greatly.