Laravel 5.4 PHP Issue in Google Compute Engine

Hi everyone.

Recently I am using Google Compute Engine to host my Laravel application. Whenever I run composer install, I received this kind of error.

Currently I am using PHP version 7.1

Problem 1
    - dompdf/dompdf v0.8.0 requires ext-gd * -> the requested PHP extension gd is missing from your system.
    - barryvdh/laravel-dompdf v0.8.0 requires dompdf/dompdf ^0.8 -> satisfiable by dompdf/dompdf[v0.8.0].
    - Installation request for barryvdh/laravel-dompdf ^0.8.0 -> satisfiable by barryvdh/laravel-dompdf[v0.8.0].

To enable extensions, verify that they are enabled in your .ini files:
    - /etc/php/7.1/cli/php.ini
    - /etc/php/7.1/cli/conf.d/10-opcache.ini
    - /etc/php/7.1/cli/conf.d/10-pdo.ini
    - /etc/php/7.1/cli/conf.d/20-calendar.ini
    - /etc/php/7.1/cli/conf.d/20-ctype.ini
    - /etc/php/7.1/cli/conf.d/20-curl.ini
    - /etc/php/7.1/cli/conf.d/20-exif.ini
    - /etc/php/7.1/cli/conf.d/20-fileinfo.ini
    - /etc/php/7.1/cli/conf.d/20-ftp.ini
    - /etc/php/7.1/cli/conf.d/20-gettext.ini
    - /etc/php/7.1/cli/conf.d/20-iconv.ini
    - /etc/php/7.1/cli/conf.d/20-json.ini
    - /etc/php/7.1/cli/conf.d/20-mbstring.ini
    - /etc/php/7.1/cli/conf.d/20-phar.ini
    - /etc/php/7.1/cli/conf.d/20-posix.ini
    - /etc/php/7.1/cli/conf.d/20-readline.ini
    - /etc/php/7.1/cli/conf.d/20-shmop.ini
    - /etc/php/7.1/cli/conf.d/20-sockets.ini
    - /etc/php/7.1/cli/conf.d/20-sysvmsg.ini
    - /etc/php/7.1/cli/conf.d/20-sysvsem.ini
    - /etc/php/7.1/cli/conf.d/20-sysvshm.ini
    - /etc/php/7.1/cli/conf.d/20-tokenizer.ini
You can also run `php --ini` inside terminal to see which files are used by PHP in CLI mode.