The table below shows image dimensions in inches (height and width), resolution in dpi, and file size in MB. The columns under the ORIGINAL SIZE list properties of the images stored on my computer; the columns under the RECALCULATED SIZE compare the width and file size of images when all have the same height (16.00 in) and resolution (300 dpi). (There are techniques to increase resolution of an image without degrading its quality, so these images practically are available in any size.)
Suppose you need a print of the image “A6 Nevada Beach 1” that would be 96.00 inches wide instead of 132.45 in. Here is how to calculate the new height:
new height = 16.00 x 96.00 / 132.45 = 11.60 inches.
Conversely, if you need a print of the same image that would be 20.00 inches high instead of 16.00 in, you need to calculate the new width thus:
new width = 132.45 x 20.00 / 16.00 = 165.56 inches.