It depends on the DPI—at 200 DPI 3.5 x 4.5 cm is equal to 275.59 x 354.3 pixels, at 300 dpi it's 413.39 x 531.5 pixels, at 600 dpi it comes to 826.77 x 1062.9 pixels and at 96 dpi it's 132.2 x 170 pixels.