Blocks: Gallery, Image Link

How can I set a link on Block Gallery Image? It would be perfekt if I can choose the target _blank or not. For the file itself I have a Blueprint for the Alt Tag, this works. I tried there with link and url but I guess it is a bit more complicated as that, but how?

I already found it. I have to write my own gallery block snippet in /snippets/blocks/gallery.php:

Once again, Kirby is great. Case closed.