[Plugin NextGen Gallery] Unable to generate thumbnails

Hi all,

Didn’t add gallery since a while and did a lot of update to keep WP ans NG up to date.
Trying to add a new gallery with new pictures, but by generating thumbnails, errors are comming up.

When I try to update the thumbnail of 1 photography :

Warning: Division by zero in /mywebsite/wp-content/plugins/nextgen-gallery/products/photocrati_nextgen/modules/ngglegacy/lib/gd.thumbnail.inc.php on line 296

Warning: Division by zero in /mywebsite/wp-content/plugins/nextgen-gallery/products/photocrati_nextgen/modules/ngglegacy/lib/gd.thumbnail.inc.php on line 309

Warning: imagecreatetruecolor(): Invalid image dimensions in /mywebsite/wp-content/plugins/nextgen-gallery/products/photocrati_nextgen/modules/ngglegacy/lib/gd.thumbnail.inc.php on line 439

Warning: imagecopyresampled() expects parameter 1 to be resource, boolean given in /mywebsite/wp-content/plugins/nextgen-gallery/products/photocrati_nextgen/modules/ngglegacy/lib/gd.thumbnail.inc.php on line 943

Warning: Division by zero in /mywebsite/wp-content/plugins/nextgen-gallery/products/photocrati_nextgen/modules/ngglegacy/admin/edit-thumbnail.php on line 53

Any idea about this issue ?

Thanks in advance.