Product images are joined!

I am having some bother with the product images on http://plantperfection.co.uk/shop/ . At the moment when you go beyond the categories and sub-cats to the products themselves, the product images have no gap between the top and bottom of each one. How can I separate these?

Another thing I am trying to sort out is that the categories and sub-categories are displaying in alphabetical order but from left to right (so a would be top left, ending in z on bottom right). THe guy I am making the web site for wants them in alphabetical order left to right - can I change this, or is it just a case of altering though the sort numbers?

One last thing (for just now!) that I am scratching my head over... I am trying to get the main page category images to display without the category name displayed underneath them. I can do this by not giving them a name but that makes it a bit awkward to navigate through the admin categories menus! Is there a way to give them a name when I creat the categories but have it NOT display under the category image itself?

I hope this all makes sense - I am loving the flexibility of Zen Cart and am struggling a bit with feeling like I have landed in at the deep end!

Many thanks for your help