[Kentaurus]

Can you add permissions for a per-user basis?

No, but you can always create a usergroup and add that only user to it

When the user inputs a new keyword will all posts with that keyword use their smilie? or does the new smilie only show in the users posts? Is the new smilie parsed so it will not interfere with current keywords? (if not might I suggest AJAX to make this check on-the-fly?

Depends on how you configure the hack. The default behavior is that if the user enters a new smilie, the smilie is only used in the new posts for that user.

You can configure the hack in such way that every time a user adds a new smilie then the cache is cleared (and, all his posts are updated the next time someone views them), but this is somehow server intensive and is disabled by default.

Please keep in mind that the smilie is only available for the user that uploaded it. Anyone else using that keyword will not get the smilie. When a user adds a smilie it is checked against his smilies (no duplicated keywords allowed) and against the forum smilies (cannot override forum smilies).

Are there restrictions on type of images? Can you add an option to limit file types?

You can restrict size and dimensions. Any image type is allowed (gif, jpg, png)

Are there instructions for adding the MySmilies dropdown for the Quick Reply box too?

I don't think that's default in vbulletin? Quick reply doesn't have a smilie dropdown. Since the hack extends the current smilies behavior I suppose if standard smilies were added to the quickreply custom smilies would appear, too.

edit...I would like to recommend adding a blank index.html to the zip for the mysmiliesvb directory for security

Thanks, will do.