Resize Image to Exact Millimeter Sizes

Millimeters are the unit of small, precise things: passport-style photos, labels, badges, stamps and cards. A single millimeter is about 12 pixels at 300 DPI, so rounding errors matter.

Each preset sets an exact width and height in millimeters, converts it to pixels at the usual print resolutions and, where the size matches a recognized standard such as an ISO paper size or an ID-1 card, says so.