Is there a way to use lightbox in a custom content type, so that you show the uploaded scaled image on the node, and when you click on it the original size pops up in lightbox?

I only succeed in showing the whole image (original size) on page, OR showing a text link to the lightbox popup. But not the combination of both (smaller image with a link to the original size).

Or do you have to be a rocket scientist to do this? ;-)

Thanks in advance!