Blueprint upload only type file images

Kirby 2 Solved ✅
1

This is my blueprint. I would like to have only the possibility to upload images (and no other files like pdf etc).
How can i do that?

title: Gallery
    pages: false
    files:
      sortable: true
    fields:
      page-meta:
        label: Page meta
        type: headline
      title:
        label: Title
        type:  text
2

https://getkirby.com/docs/panel/blueprints/file-settings