Background size...

I'm new to Web design and this is something I need to know but it's been bugging me for quite a while now.

How do you make your background image so its the same resoulution size on whatever computer you go on?

usually when I scroll down, there is left over white space on the side and bottom but i just want the image to fit... =/ =(

you can use background-repeat: repeat; if the background is repeatable.

setting your background to 100% of the screen will distort the image, so you have to use javascript to detect the user's browser size

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if you are talking about when you decrease the browser size and scroll over, there is white space, then this is due to margin: 0 auto; try setting the parent tag to min-width: (value of child width)