How are you stretching it with HTML?? As far as I know, there is no way to actually 'stretch' (as in reproportion) an image that is set as a background.
However, depending on the content of the image you are using, it may be appropriate to tile it -- that is, cause it to repeat itself over and over until it fills the entire space. This effect can be acheived using the CSS property/value pair, "background-repeat:repeat;".
You can also make the picture center itself in the available space, allowing your background-color to show in the areas it does not cover. In this case, use these two statements: "background-repeat:no-repeat;" and "background-position:center;". If you are using the picture as the background of the entire page (not just in a small box), you might want to also add this code - "background-attachment:fixed;" This will make sure that the picture doesn't scroll away if the user needs to scroll the page to see all of it's content.
Let me know if this helps! -----------------------
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