(aspect-ratio (/ (car dim) (cdr dim)))
(width (round (sqrt (* aspect-ratio 1000000 megapixels)))))
(cons width (round (/ width aspect-ratio)))))
(aspect-ratio (/ (car dim) (cdr dim)))
(width (round (sqrt (* aspect-ratio 1000000 megapixels)))))
(cons width (round (/ width aspect-ratio)))))