Banners & Ad Blocker

    I have banners on my website that I use as signs, not as
    ads, but they are blocked by my ad blocker program. Even
    though I turned off the ad blocker program, I'm thinking my
    banners may be blocked on some visitors's computers. So, I'm
    wondering is there a way to make my banners where they won't
    be blocked by ad blocker programs? What is it about banners
    that causes them to be blocked? Is it the size?