Bonjour,

commentaire du fichier config
// php_extension_in_urls : if true, the urls generated for picture and
// category will not contain the .php extension. This will work only if
// .htaccess defines Options +MultiViews parameter or url rewriting rules
// are active.
$conf['php_extension_in_urls'] = true;

// category_url_style : one of 'id' (default) or 'id-name'. 'id-name'
// means that an simplified ascii represntation of the category name will
// appear in the url
$conf['category_url_style'] = 'id';

// picture_url_style : one of 'id' (default), 'id-file' or 'file'. 'id-file'
// or 'file' mean that the file name (without extension will appear in the
// url). Note that one aditionnal sql query will occur if 'file' is choosen.
// Note that you might experience navigation issues if you choose 'file'
// and your file names are not unique
$conf['picture_url_style'] = 'id';

En fichier de conf local tu peux donc ajouter
$conf['picture_url_style'] = 'id-file';

oui ben c'est ça...