Agree with PP to send something generic if you can't figure it out...the shutterfly thing works too...
But ladies, I think we all need to do a better job with not worrying so much about what other people think and what "proper" etiquette is these days - i think if you mean well, and if you're kind and decent to people - that's good enough! There is ALWAYS going to be someone out there who thinks what you have done isn't good enough...why do we do that to ourselves? Why do we worry so much?
OP - you'll figure it out, and I am sure whatever you do, it will be fine. We have to ask ourselves - if a THANK YOU card isn't good enough, aren't our priorities a little off? There have got to be more important things in life to worry about.