storage_backend/storage_thumbnail/security/ir.model.access.csv

1	id	name	model_id:id	group_id:id	perm_read	perm_write	perm_create	perm_unlink
2	access_storage_thumbnail_edit	storage_thumbnail edit	model_storage_thumbnail	base.group_system	1	1	1	1
3	access_storage_thumbnail_read	storage_thumbnail read	model_storage_thumbnail	base.group_user	1	0	0	0