i'm trying to get

Hi, i'm trying to get the sub menu on my navigation to appear horizontal rather than vertical, you can view the website here: http://www.artificialsupergrass.co.uk and if you hover over the products drop down ( it's currently a mess sorry about that ) i'd like to be able to use images rather than titles and have them go edge to edge within a horizontal menu e.g. a budget grass image, premium grass image all aligned next to one another without any space around them. I've tried multiple image plugins, i've attempted to modify the code but it's having none of it.