Where does the photo go
Nowhere. The photo you pick is cut into pieces inside your browser, and your progress is kept in this device's own storage. Nothing is uploaded to our servers, which also means we have no way of seeing it.
The same holds when you invite a friend. The photo travels straight from the host's browser to your friend's. Our server only relays the signals the two browsers need to find each other — the picture itself never passes through it.
When you finish a puzzle or delete it from your list, the photo goes with it. Clearing your browser data removes it too.
Which photos make good puzzles
Every piece needs a clue on it. Photos with colour and detail spread evenly across the frame work best, while a big expanse of sky or a plain white wall will stall you right there — though some people pick those on purpose.
Portraits work well when the face is large in the frame. Group shots where everyone is small are better at a lower piece count. As for resolution, anything over about 1000 pixels on the long edge is plenty, and every modern phone photo clears that comfortably.
How many pieces
If this is your first one, try 48 or 100 pieces and go from there. Roughly: 48 pieces takes a few minutes, 200 takes half an hour or so, 500 runs to a couple of hours, and 1000 is something you come back to over several days. Type your own number and it goes up to 2000.
Because the grid is fitted to your photo's aspect ratio, the real count lands near the number you picked rather than exactly on it. Choose 1000 for a tall photo and you may get 990 or 1008.
Solving it with friends
Open a board, press invite, and you get a link. Whoever opens it joins the same board straight away — no sign-up, no install. Up to eight people at once, and you can see which piece each person is holding.
Making one as a gift
Some people turn a single photo into a puzzle for a birthday or an anniversary and send the link. The other person just taps it, and the original photo appears as they finish. Keep it around 100 to 300 pieces — much higher starts to feel like a chore rather than a present.