[Gallery: Template] How to change the link?

Hi everybody,

i try to change link in the template. usually if you click on the thumbnail of the gallery it links to the original, uploaded image with its original file-size. but when i upload images wordpress generates “thumbnail”, “medium” and “large” images of the uploaded ones.

how do i change the link from original to large (in my case max. 592px width). i built in a jquery lightbox in my template, it works perfect but the original image size is just to big … thanks alot!