ImageMagick is a CLI tool which allows you to convert images to different formats.

It refuses to convert graphical images to PDF.

convert-im6.q16: attempt to perform an operation not allowed by the security policy `PDF' @ error/constitute.c/IsCoderAuthorized/421.


Simple to fix by going to the config file of ImageMagick:

/etc/ImageMagick-6/policy.xml

Remove this line:
<policy domain="coder" rights="none" pattern="PDF" />