I am also interested in the script here but when I inserted it into my page two issues arised.
1) The picture that is supposed to be clicked ended up on the top of the page overlaying the form underneath. I need it to be positioned in a certain place.
2) I need to be able to position several marks on the same image. How do I do that?
And as a bonus, I need these marks to be able to be transferred to a pdf along with everyting else in the form at the end of completing the form.