Gallery Shortcode: using link attribute to link to a specific image size

When is used, it calls the original image file source.

It it possible to create a shortcode filter that links to a specific size, like:

or

(referring to an additional image size created with add_image_size() in functions.php.)

I found something very close that works here:

http://oikos.org.uk/2011/09/tech-notes-using-resized-images-in-wordpress-galleries-and-lightboxes/