On my system I have ImageMagick and its documentation installed:
$ apt-cache pkgnames imagemagick imagemagick imagemagick-6.q16 imagemagick-dbg imagemagick-doc imagemagick-common I can access convert's man page, which tells me SEE ALSO ImageMagick(1) if I want to know more.
man ImageMagick says No manual entry for ImageMagick.
And finally, man -k imagemagick says:
quantize (5) - ImageMagick's color reduction algorithm. How do I access ImageMagic's man page on my system?
Additional information
Above I was mistaken. apt-cache pkgnames listed packages are "not necessarily available to download, installable or installed" (ref. APT-CACHE(8)). So, my command did not list the installed packages.
Digging more, I ended up with
$ apt list imagemagick* Listing... Done imagemagick/xenial-updates,xenial-security,now 8:6.8.9.9-7ubuntu5.4 amd64 [installed] imagemagick-6.q16/xenial-updates,xenial-security,now 8:6.8.9.9-7ubuntu5.4 amd64 [installed,automatic] imagemagick-common/xenial-updates,xenial-updates,xenial-security,xenial-security,now 8:6.8.9.9-7ubuntu5.4 all [installed,automatic] imagemagick-dbg/xenial-updates,xenial-security 8:6.8.9.9-7ubuntu5.4 amd64 imagemagick-doc/xenial-updates,xenial-updates,xenial-security,xenial-security 8:6.8.9.9-7ubuntu5.4 all So, apparently, imagemagick-doc was not installed. Nevertheless, this package installs the www documentation (/usr/share/doc/imagemagick-doc/www) and not the man one.
Checking the content of the imagemagick package does not give away what the name of its man page is, or at least, I am not able to figure it out.
$ dpkg -L imagemagick | grep man /usr/share/man /usr/share/man/man1 /usr/share/man/man1/stream-im6.1.gz /usr/share/man/man1/display-im6.1.gz /usr/share/man/man1/animate-im6.1.gz /usr/share/man/man1/mogrify-im6.1.gz /usr/share/man/man1/composite-im6.1.gz /usr/share/man/man1/montage-im6.1.gz /usr/share/man/man1/import-im6.1.gz /usr/share/man/man1/identify-im6.1.gz /usr/share/man/man1/conjure-im6.1.gz /usr/share/man/man1/convert-im6.1.gz /usr/share/man/man1/compare-im6.1.gz Bug report here
I've opened a bug report here. Let's see if someting comes up.