Last modified: 2008-02-14 01:54:25 UTC
Using imagemap to link to an external URL with '&' in it will break, the & is converted to &. (that is & ; in case it renders it) So a link to www.&.com will go to www.&.com (again & ;).
www.&.com is not a valid domain.
However, something like "en.wikipedia.org/w/index.php?title=Main_Page&action=edit" is valid, and also contains an & symbol. I just used the invalid www.&.com to demonstrate how the & is treated.
Providing a real example would have helped. :)
Here's a sample ....
Image:Foo.jpg|200px|picture of a foo
poly 131 45 213 41 210 110 127 109 [http://en.wikipedia.org/w/index.php?title=Display&action=history]
I can confirm that the resulting link is double-HTML-escaped, leading incorrectly to http://en.wikipedia.org/w/index.php?title=Display&action=history
Have put the example live at http://www.mediawiki.org/wiki/Extension:ImageMap/bug_11504