Why do some regions have no number?
Very small regions are still outlined so the shape stays accurate, but skip the number since text that small wouldn't be legible once printed. Raise the minimum label size to number more regions, or fewer, larger ones.
How many colors will I need?
It depends on your photo — the tool reports the exact count used. High-contrast, simpler photos naturally use fewer colors than busy, gradient-heavy ones.
Can this print at a specific canvas size?
Yes — the SVG is sized in millimeters from the output width you set, so it prints true to size at that width.
Is anything uploaded?
No. The photo is processed entirely in your browser and the tool is free with no sign-in.