Change the Default Gravity Forms AJAX Spinner - If you want to change the default Gravity Forms AJAX spinner, Gravity Forms provides us with a filter to do so: gform_ajax_spinner_url. Paste the following code into your installed and activated custom snippets plugin.

gravity-forms-ajax-spinner

add_filter( 'gform_ajax_spinner_url', 'cwwp_custom_gforms_spinner' );
/**
 * Changes the default Gravity Forms AJAX spinner.
 *
 * @since 1.0.0
 *
 * @param string $src The default spinner URL
 * @return string $src The new spinner URL
 */
function cwwp_custom_gforms_spinner( $src ) {
 
    return get_stylesheet_directory_uri() . '/images/loading.gif';
    
}