gnus-blocked-images

gnus-blocked-images is a variable defined in `gnus-art.el'.
Its value is

gnus-block-private-groups

Documentation:
Images that have URLs matching this regexp will be blocked.
This can also be a function to be evaluated. If so, it will be
called with the group name as the parameter, and should return a
regexp.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 24.1 of Emacs.