<img alt="toyto logo" src="./images/sponsors/toyota.gif" />Of course everything was fine in IE, Opera an Safari.
<img alt="honda logo" src="./images/sponsors/honda.gif" />
I found that my AdBlock Plus was blocking my banners because the following default filter in AdBlock Plus
/[/^a-ik-z\d=+](get|web)?_?spons?(or(ed|s))?_?(links?(auto)?)?(pots?)?(\W|_|$)(?!.*sigalert)/The solution was to rename sponsors folder on my server to something else. I choose to rename it to friends. It worked.