Install ImageMagick 7 on Ubuntu
Installing Dependencies for ImageMagick
sudo apt update
sudo apt install imagemagick
sudo apt install php-imagick
sudo systemctl restart apache2
php -m | grep imagick
Using Imagick with PDF Files
ImageMagick was not designed to securely handle untrusted PDF files. Enabling PDF file handling as shown below is dangerous if any malicious PDF files are ever processed.
Additionally, attempting to work around ImageMagick’s PDF security issues by using Ghostscript directly is also dangerous as Ghostscript is also vulnerable to exploitation when processing malicious PDF files.
In order to allow ImageMagick to process PDF files, you must SSH into your server as root and edit the following file:
/etc/ImageMagick-6/policy.xml
Locate the line:
<policy domain="coder" rights="none" pattern="PDF" />
Comment out this line by replacing it with the following:
<!--<policy domain="coder" rights="none" pattern="PDF" />-->
Finally, restart PHP:
replace X.Y with your php version
sudo service phpX.Y-fpm-sp restart
or
sudo systemctl apache2