swapping images

 Hi
I'm new to this list so please forgive me if this has come up already. 

Has anyone come up with a solution for making swap-image javascript
functions accessible? I know that ideally these should be avoided, but I am
keen to push the boundaries of the guidelines a bit and see what is
possible. My solution so far has been to simply create a D tag (and a
longdesc attribute for the image tag) for the default image and then
describe what each image will look like as the user holds their mouse over a
different link (for an example see
http://www.nzhistory.net.nz/dnzb_exhibs/index.htm ). 

Is this an 'acceptable' solution? Are there better ways of doing this?

Thanks
Jamie Mackay
Web Editor
Ministry for Culture and Heritage
New Zealand