wot firewall is it.............if its norton or outpost it might be ad blocking the images. if so u can turn the ad blocking off.
some pictures have adware and spyware cookies associated with them (at least i think thats how it works), so your firewalls ad blocker will block such images if they are in its list of adware thats to be blocked.
make sure u have security level for inernet explorer set to "medium" for "internet"
dsl surfing without a firewall is a bit risky............turn it on and keep it on!