The passport photo spec is in millimetres, your printer works in pixels, and most tools hand back something that looks correct on screen and prints 2-3mm out — the one thing that gets an application rejected. Photo Studio works in millimetres from the start, with 32 built-in document sizes across 21 countries. Crop to spec, then print a sheet that measures correctly against a ruler. It also straightens scans and resizes to a target KB. Nothing uploaded. Free to start; paid from $4.99.