Malicious Attack: Malicious Image request 2

This morning I googled in order to get some information about a phone call we received in order to see who was calling us as the caller ID did not give out anything but the phone number. The one website I clicked on was marked as safe by Norton, but Norton immediately notified me that it had been blocked and that it was a high risk. Although I quickly left that website it was blocked two more times by Norton.  All three blocks were within 6 seconds. I'm happy that the attack was blocked, but I'm wondering why the site was marked safe by Norton when I looked at the googled sites.

Holly