Banner Expires after....

In the banner manager, ther is an entry under the"expires" section that says the banner will expire after a certain number of impressions or views. If this number is set to 0 does that prevent the banner from being displayed at all Or does that indicate the the banner will always be displayed? Also, I have some banners that are showing up as blanks boxes. I can't seem to see why they would be blank other then that the spam filter here in the office is preventing them form displaying any suggestion?

The 0 impressions will show ...

What are the settings on the Banners that do not show?

Are you able to open the Banner image itself in your browser directly?

Thanks, the problem with the blank impressions is the spam filter here in my office, I will need to work around that for testing.

Try checking:
1 name of image
2 name of directory

Right now, you are probably using:
/images/banners

and that won't display with some things ...

Test with:
/images/fred

Or, the image names:
my_banner.jpg

try using:
my_fred.jpg

do they work now?