I've seen a couple of requests for this so today I decided to tackle it.

This mod adds a new bbcode tag that'll hide what you wrap with it. It works with text and images. Clicking on the show button, reveals the block.

Tested in IE, Firefox, Opera and Netscape.

Can be seen and tested here:

http://www.pchelp4free.myby.co.uk/forum/Blah.pl?

Username: tester
Password: tester