Recently the new php7 has been released. However, when I am trying to install the gd package, the library can not be found.
I have tried through
sudo apt-get install php70-gd
sudo apt-get install php70-php-gd
PHP7 packages for Ubuntu including
php7.0-gd can be installed via PPA for PHP by Ondřej Surý:
sudo add-apt-repository ppa:ondrej/php sudo apt-get update sudo apt-get install php7.0-gd
As MacroMan stated, under Ubuntu 16.04 you don't need to add the repository any more. Simply issuing
sudo apt-get install php7.0-gd works.