Many photographers want to have a link to their work and / or a link to the licence. So it would be fine if we could have copyright and credit fields with optional input fields for links. Yes, I can write this in description, but I think the better place would be copyright and credit fields.

For example if I use pictures from Flickr like this there's the condition

Quote

You must give appropriate credit, provide a link to the license

In the best case, next to the credit field would be a dropdown field for various licenses:

CC BY 2.0 (http://creativecommons.org/licenses/by/2.0/legalcode/)
CC BY-NC 2.0 (https://creativecommons.org/licenses/by-nc/2.0/)
CC BY-NC-ND 2.0 (https://creativecommons.org/licenses/by-nc-nd/2.0/)

... (and so on)

For the Copyright field could there be the text field (in my example I would write "Michael Wen / Flickr") and a field of type URL. In frontend is then shown "Michael Wen / Flickr" (in my example).

I must be misunderstanding something. When you go to submit images in Gallery, this is already possible.

You can optionally set the same copyright and/or credit for all images, or click each image you upload and set the individual values in the right handle panels that show.

No, I mean another point.

We need for both settings an additional field for setting of URLs.

Look at an example from an album in our gallery: https://www.psoriasis-netz.de/community/gallery/image/29820-caridee-english/

There are credit and copyright, but they should have links.