'pkg upgrade' complains about the missing dependencies, but 'pkg check -d' doesn't fix anything

[Yuri]

This looks like the inconsistent behavior:
# pkg upgrade
Updating repository catalogue
pkg: Missing dependency matching 'graphics/imlib2'
pkg: Missing dependency matching 'graphics/imlib2'
pkg: Missing dependency matching 'graphics/libcaca'
pkg: Missing dependency matching 'graphics/imlib2'
pkg: Error while trying to install/upgrade packages, as there are 
unresolved dependencies:
graphics/giblib: graphics/imlib2
graphics/gstreamer-plugins-libcaca: graphics/libcaca
graphics/libcaca: graphics/imlib2
graphics/scrot: graphics/giblib

# pkg check -d
<nothing is done>

pkg-1.2.6

Natural question is why doesn't 'pkg check -d' find and correct the same 
dependency problems?

Yuri