Invisible "D" links for images illegal?

We want to add an invisible link for the long description of the images of our site for validating with accessibility validators.

The example looks like this:

<img class=”accessibility” src=”/images/accessibility.jpg” longdesc=”/wheelchair.html” alt=”A wheelchair. A symbol for accessibility” /><span class=”dlink”><a href=”/wheelchair.html”>D</a></span>, using in CSS: dlink {visibility: none}

Can we be punished for that, even if the link is legally added in the longdesc tag?

If you want to see the source code see the test page here: [url]http://www.webnauts.net/test.html[/url]

Also in #SEO _↴