menu images load slow - mainly safari and chrome browsers

Hello!

First off - superb module, love it, use it all the time. However, there is a slight bug with the latest one ive been working on. I usually dont, but this time i used the rollover function that came with the module.

In total i have 7 links, which means 14 different png images. They works perfectly fine in Firefox and Internet Explorer, but when i tried loading the site in Safari or Chrome, some buttons didnt load properly. It showed a question mark (as if it was bugged), and you have to roll your mouse over to make it show. It looks like some pre-load problem or something.

And when it does load after rollovering, the buttons stay as the 2nd image, not the first.
That results in pushing parts of my layout disgustingly.

I was wondering if there is any fix to this - a cache problem, perhaps? or anything?

THANKS! Great module!