I've updated the link/image restriction code to now include signatures, which while images and links without permission were not allowed by the rules, this was not enforced by the forum code.
Now it is.
Attempts to go around it result in a *link removed* text appearing instead, which indicates the rule breaking as well, and will help moderators to still spot spam robots.
The blanket link restriction code for
posts that returns an uninformative error message is still the only option we have at the moment, as other link restriction codes so far tested do not work with our version of the forum software. There're still potential work arounds, and if worst comes to worst I can attempt the programming myself or hire help, so it is just a matter of time God willing.
The code does not restrict image use from the media gallery using the special media gallery code -- but I am going to rule against the use of media gallery images as well for signatures as signatures with images simply take up too much space and make it less easy to read forum posts.
We have extra-large sized user profile 'avatar' images, and we have the media gallery, I think this more than suffices.