BO > Catalog > Add & Delete Product Accessory
When you attempt to delete product accessory, an error prompt “Bad Size” is generated and you have to manually delete the accessory from the database.
Bug Fix found on github: https://github.com/PrestaShop/PrestaShop-1.4/commit/38c46b70f4cef35f67a9ce55d5a5cde0e22008f4
Easy solution was to copy the entire file from GitHub and replace with your file (adm/tabs/AdminProducts.php).
There are some additional postings found on PrestaShop Forum as well.
Receive “Bad Size” error when I try to delete Accessories in product: http://www.prestashop.com/forums/topic/177462-solved-receive-bad-size-error-when-i-try-to-delete-accessories-in-product/
GitHub PrestaShop v184.108.40.206: https://github.com/PrestaShop/PrestaShop-1.4/commit/38c46b70f4cef35f67a9ce55d5a5cde0e22008f4