ImageMagick could convert multiple images to a single pdf.
How-can-i-convert-a-series-of-images-to-a-pdf-from-the-command-line-on-linux
How could reverse the operation?
Convert a pdf of pages to multiple images?
Try the solution
$ convert test.pdf test-%02.png
convert-im6.q16: attempt to perform an operation not allowed by the security policy `PDF' @ error/constitute.c/IsCoderAuthorized/408.
convert-im6.q16: no images defined `test-%02.png' @ error/convert.c/ConvertImageCommand/3258.
gs was installed
$ gs --version
9.26
Ubuntu version
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 19.04
Release: 19.04
Codename: disco
/etc/ImageMagick-7/policy.xml
should sort out the issue: add<policy domain="coder" rights="read | write" pattern="PDF" />
before</policymap>
– andrew.46 Oct 18 '19 at 2:57convert-im6.q16: not authorized filename.pdf @ error/constitute.c/WriteImage/1037.
– M.Viking Dec 10 '19 at 14:26