cannon.danielc wrote:

I would strongly support this. There is quite a strong consensus against using images in sigs, and I think the
best way to restrict this is to disable it technically rather than this obnoxious "bullying" of other editors to
change their sigs. If anything, it's just a waste of server space and time to have a ten page dispute about
every individual user's signature. I'd also like to recommend that a restriction of signature length be
implemented, although I don't believe there to be strong consensus for this on enwp.

emddudley wrote:

Anyone wishing to furthur discuss the signature issue, please do so at
http://en.wikipedia.org/wiki/Wikipedia_talk:Sign_your_posts_on_talk_pages#Imposing_signature_restrictions.
Try to keep discussion here about actually implementation the image restriction.

davidcraig5 wrote:

The poll seems to have closed and it looks like there is decent support for some
changes.

ligulem wrote:

Template calls should be disabled as well. The current method which adds subst
to template calls removes just the first level of template calls and leaves
stuff like:

:: <em>[[User:Colin Keigher|Colin Keigher]]</em> ([[User talk:Colin
Keigher|Talk]]) {{#if: Canada |
{{country_flagicon|Canada|Canada|size={{{size|}}}}}
}} 06:38, 19 December 2006 (UTC)

on pages (this was a user that used {{flagicon|Canada}} in his sig). See also
[[bugzilla:2777]]

(In reply to comment #4)

Template calls should be disabled as well. The current method which adds subst
to template calls removes just the first level of template calls

This is another bug, so that I have created bug 12495 for this specific problem.

The rest of this report is a request for a new functionality, not a bug report, so I am changing the severity accordingly.

RSYQFIOJGWZA wrote:

The original discussion was archived to http://en.wikipedia.org/wiki/Wikipedia_talk:Signatures/Archive_1#Imposing_signature_restrictions .

I feel the consensus there is outdated, there's been more talk about signatures lately (I don't remember in what direction).
If still current, reopen or better file a new bug in Wikimedia>Site configuration with another bug, requesting this feature in MediaWiki>User preferences, as blocker.