Well if you know the size of the image you can build the size dynamically. For example if the image is 400 pixels wide by 200 pixels high and are stored in variable iWidth and iHeight, then your window.open would be similar to:
Code:
window.open(<url here>, "NewWin", "width=" + iWidth + "px,height=" + iHeight + "px" );
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Joe (
Microsoft MVP - XML)