Sliced Menu with Mouse-over in Header – Spaces

I’m attempting to use a sliced menu with mouse-over images and links in my header. I know it would be better to use CSS to do this, but I really have no idea how to go about getting the same effect in that method. Instead, I used the old-fashioned table method but am coming up with spaces between my images. Example:

https://www.roman1productions.com/blog/

On top of that, the background seems to be shifting as well.

Is there some way to fix the space issue or am I going to have to learn how to do this with CSS instead? Any help would be greatly appreciated.