Image size on different res screens

Hi there

I am looking to use an image in the background of my flash site. I am creating it in Flash CS3.

I use a 1024 x 768 res screen.

I want to know if i made the image 1024 x 768, the image would look ok on my screen. How would it look on other people’s screens if they have a higher res like 1280 x 800 or higher, would the image have space around it or would it strech

What would i do to, i don’t want the image to strech and distort and i don’t want space round it. If i wanted to accompany all screen res what is the ideal size. The image will be put in externally via code in flash as well.

I would experiment, but my screen res is max at 1024 x 768.

Thanks for any ideas and help!