Invisible "D" links for images illegal?

[Webnauts]

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]/images/accessibility.jpg[/img]<span class="dlink">D</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: http://www.webnauts.net/test.html

[incrediblehelp]

Why do you think this would be an issue?