debian 7.1喘息上的php5 gd破损包装

这是尝试安装时显示的错误

root@BH13:# apt-get install php5-gd
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 php5-gd : Depends: libt1-5 (>= 5.1.0) but it is not installable
           Depends: libvpx1 (>= 1.0.0) but it is not installable
E: Unable to correct problems, you have held broken packages.

php版本

root@BH13:# php -v
PHP 5.5.38-1~dotdeb+7.1 (cli) (built: Jul 21 2016 18:33:48)

它不允许我安装php5-gd来使用php图像库

这在sources.list中

deb http://http.debian.net/debian/ squeeze-lts main contrib non-free
deb http://packages.dotdeb.org wheezy-php55 all
deb-src http://packages.dotdeb.org wheezy-php55 all
deb http://packages.dotdeb.org wheezy all
deb-src http://packages.dotdeb.org wheezy all
deb http://packages.dotdeb.org squeeze all

deb http://ftp.nl.debian.org/debian/ wheezy main
deb-src http://ftp.nl.debian.org/debian/ wheezy main
deb http://security.debian.org/ wheezy/updates main contrib
deb-src http://security.debian.org/ wheezy/updates main contrib

这是我更新之前的php版本： PHP版本5.4.45-0+deb7u9

和以前的资料来源

deb http://http.debian.net/debian/ squeeze-lts main contrib non-free
deb http://packages.dotdeb.org wheezy-php55 all
deb-src http://packages.dotdeb.org wheezy-php55 all
deb http://packages.dotdeb.org wheezy all
deb-src http://packages.dotdeb.org wheezy all
deb http://packages.dotdeb.org squeeze all

deb http://ftp.nl.debian.org/debian/ wheezy main
deb-src http://ftp.nl.debian.org/debian/ wheezy main
deb http://security.debian.org/ wheezy/updates main contrib
deb-src http://security.debian.org/ wheezy/updates main contrib

谢谢你的支持