Why not use another site to do that, I got a clickpic site and if I ever need to password protect any images.
I also have a Zenfolio-site that allows me to do that. And over there I can download bigger files so people can download them straight from there if I they want to.
And Zenfolio being an American site, and with the rate of the dollar. It was a bargain to have (and a friend of mine referred me to it, so I got a little discount for the fee).
How about that for a solution - surely cheaper than going for super-pro at Clickpic...