4 Deprecated sur image_graver en PHP 8.1

Bonjour,

J'ai 4 Deprecated en SPIP 4.1.17 et PHP 8.1 :

PHP Deprecated:  strpos(): Passing null to parameter #1 ($haystack) of type string is deprecated in .../ecrire/inc/filtres_images_lib_mini.php on line 1166
PHP Deprecated:  strlen(): Passing null to parameter #1 ($string) of type string is deprecated in .../ecrire/inc/filtres_images_lib_mini.php on line 1169
PHP Deprecated:  strpos(): Passing null to parameter #1 ($haystack) of type string is deprecated in .../ecrire/inc/filtres_images_lib_mini.php on line 1180
PHP Deprecated:  str_replace(): Passing null to parameter #1 ($search) of type array|string is deprecated in .../ecrire/inc/filtres_images_lib_mini.php on line 1182