Rollover over/out affect with button

I have quite a few regular buttons with up/over/down/hit states, however now my client wants an image next to my buttons to fade in when the button is rolled over, and then fade out on rolloff.

The image that fades must not be a hit area.

So basically each button will have a small image fade in next to the button when the user rollsover, and then the image fades away on rolloff.

Im just after a fairly simple solution to this as I have many buttons and dont want to have to rebuild each button from scratch.