Problem with menu sliding doors

I have a problem with the menu on this site

As you can see each menu item has a small part of the image which shouldnt be there at the top left, Im using sliding doors technique, how can I fix it? thanks

I think you’ve set a transparent background for the top-left corner of the inner image (although you’ve correctly got a grey background for the bottom-left corner), which means the image behind is showing through in that corner.