Customizing the Layout field

I have this code in the blueprint:

layout:
  type: layout
  layouts:
    - "1/1"
    - "1/2, 1/2"
  fieldsets:
    - image

When I click to create a block, a popup window opens up:

I wonder if it is possible to customize it so that there would only be a single field for uploading an image?

Do you mean, only Kirby images, not images from external urls?

You can tweak all standard blocks to your liking by overwriting the blueprints/snippets in the site folder/in a plugin

So you wouldn’t customize the layout field, but the image block.

Thank you!