Nav bar help

I just finished the majority of the code for my simple nav bar and I'm
having a few issues.

When I use IE everything works as planned except that when the resize is to
small the link images scale down so small that nothing happens. I want them
to have fixed size and rather have a scroll bar. (later I might have it
where they go horizontally or something but for now I'm not worried about
catering to people who want to view the page under 450pixels in width).

But I also have 2 issues in firefox. When the button is clicked there is a
border that is shown and also the state goes back to the original. In IE the
button does not change unless a new nav button is clicked but in IE it is
released once the user lets off the mouse button. What can I do to fix

Also is there any way to optimize the css code I used. It seems very
redundant to use the same code for different imagse but its the only way I
can get it.

Thanks for any help,