add_filter( 'wpsl_templates', 'custom_templates' );

function custom_templates( $templates ) {

    /**
     * The 'id' is for internal use and must be unique ( since 2.0 ).
     * The 'name' is used in the template dropdown on the settings page.
     * The 'path' points to the location of the custom template,
     * in this case the folder of your active theme.
     */
    $templates[] = array (
        'id'   => 'koloreko',
        'name' => 'Koloreko template',
        'path' => get_stylesheet_directory() . '/' . 'wpsl-templates/koloreko.php',
    );

    return $templates;
}

add_filter( 'wpsl_thumb_size', 'custom_thumb_size' );

function custom_thumb_size() {
    
    $size = array( 150, 150 );
    
    return $size;
}