[Plugin: NextGEN Gallery] adding images classes / links

Hi

I have just set up a wordpress blog (www.elmurphy.co.uk) and have installed Nextgen. I have the basic functionality working but I want to use the more advanced features like the shutterset plugin – but I cant for the life of me figure out how/where to add the class on the images.

I have tried the advanced image settings under both class and rel but have had no joy. Could someone please explain where tags like class=”shutterset” are entered

thanks