Adding custom preview image to custom block style

Hello. I have used the register block style to sucessfully add pre-set style options to the group and image blocks. This is great. For example, using:

register_block_style('core/group',
    array(
        'name'         => 'outlined-box',
        'label'        => __( 'Outlined Box' ),
        'style_handle' => 'outlined-box',
    )
);

However when you look at the style tab on the block editor it uses the default images. For example the group block just shows a basic text image and the image block the default image. I want to add my own images on the preview so that they visually represent what the style they create when selected.

How do I set the preview image in the register block style?