how to link an image to a master category

I want to link a full image to a master category. Please take a look at my site http://www.uhotstyle.com. When clicking on handbag, it shows a small image in the left corner. But I want this image be shown all the middle area. How can I do that?

You can set the display size of many different images in admin > Configuration > Images.

which choice should I make from admin > Configuration > Images?

Test 'em and see...
:)

Seriously, my first picks would be Heading, Subcategory or Top Subcategory.

Don't work. I try all your suggestions.

Here is image from

Category Image: by browse button

Were you trying to attach a screenshot?
One of the Images items will allow your category pic to get bigger... but it won't stretch it larger than the actual pixels of the image file. How many pixels is the file you are displaying? When I stretch it with Edit HTML, it gets very blurry, as if there is no more there to show. Put a larger image in that place and see what happens.

By the way, it occurs to me that, while your site layout may be "Copyright © 2007 Louis Fashion House." after you have customized the graphics, it is not "Powered by Micro Tech, Inc. & uhotstyle.com" - it is powered by Zen Cart. Please don't claim to have written the code that makes your cart function.