Firewalls block only some graphics?

[joyforlife]

I would like to get a better understanding of why having a firewall with Norton Internet Security would block users from seeing SOME graphics and not others. I designed a page recently with 5 banners on it. 2 of them show up normally. 3 do not show up at all! The coding is identical for all 5 of them, except for the file name.

I am tearing my hair out! Because if I cannot see the page normally with Norton running, then there are going to be a lot of people who will not see it normally.

So, I am trying to figure out why the 2 visible ones ARE visible and apply that "trick" to the invisible ones!

Here is the web page:
http://destinationwinnipesaukee.com/banners.html
(all of the graphics in the header show up fine for me. Under the heading "Choose the banners..." the bottom 2 banners show up. But the 3 top banners do not)

AAAAHHHHH! What am I missing here?

Thanks in advance!

[felgall]

The top three banners are common ad sizes and the firewall is set to strip out ads. The bottom two banners are not in the list of common ad sizes that the firewall recognises as ads and they therefore get through and are displayed.

[WebJoel]

....So, I am trying to figure out why the 2 visible ones ARE visible and apply that "trick" to the invisible ones! Gee... I rather hope that yo do not figure out how to do this. :eek: I have 'adBlockPlus' and alot of ads never appear when I browse (including ads that normally appear on, um, excellent forums :D ).

[felgall]

The 'simple' trick is to make sure your images do not use the same sizes as are used for standard advertising. Of course this will mean that you can't add them to advertising sites that require them to be those set sizes.