Subcategory Thumbnail

Hello I am using your plugin i just want to ask a little help I have parent category and 2 subcategory i assigned both category different thumbnail here is code what i am using now i want each subcategory have to different thumbnail is this possible ?

$thiscat =  get_query_var('cat');

$child = get_category_children( $thiscat, $before = '', $after = ',', $visited = array() );

cfi_featured_image( array( 'size' => 'thumbnail', 'title' => 'This is a test...', 'class' => 'my-image', 'alt' => 'My image','cat_id' => $child ) )

but this only return one thumbnail even i have two sub category Thanks

https://www.ads-software.com/plugins/category-featured-images/