Background resizing?

1

can anyone help me figure out how to make the background of my site resize so that when someone uses a smaller res or resizes the window, it doesnt cut off half the background? but then if i make the background smaller and the person is using a higher res it will get really pixelated? do i have to use a table and set the backgorund of teh table as the background i want to use? but then it will not resize if the person resizes their window.