Is there a limit on how many photos I can add, or how big they can be?

Each file must be under 50 MB and photos are saved 20 at a time, but you can choose hundreds at once and there is no per-guest total — the only overall cap is the event’s own photo limit.

• 50 MB per file. This is the hard ceiling and the storage itself enforces it, so an oversized file cannot slip through.
• Saved 20 at a time. The tray holds twenty. Choose more than that from your library — up to 1,000 in one go — and the rest wait their turn: each batch of twenty is sent and saved automatically, and the page shows how many are saved out of how many. Keep the page open until it is done.
• No per-guest total. Upload as many batches as you like.

If the page is closed or reloaded part-way, the photos already in the tray are kept on your phone, but a web page cannot reopen the rest of your selection on its own. The page tells you how many still need choosing: choose them again (the whole selection is fine) and any already saved are skipped.

Photos are also shrunk in your browser before they are sent: anything longer than 4096 pixels on its longest edge is scaled down and re-saved as a JPEG. That is why a large photo rarely hits the 50 MB ceiling, and why uploads finish quickly on venue WiFi. Videos are sent exactly as they are, so it is videos that run into the ceiling.

The one limit that is not about your phone is the event’s own photo allowance, which belongs to the host — see Why does it say the event is full?.