No. They stay on the phone and upload when you next reach Wi-Fi. The only risk is losing or breaking the phone mid-trip.

You can, but it is enormous: a minute of 4K can run to several hundred megabytes. Wait for Wi-Fi.

Queue uploads overnight while charging, back up photos first, and leave video until you are home.

It depends on the backup service used. Some let you download it back from the cloud any time, while others set their own retention terms. This is specific to that cloud provider, not something this tool controls.

Technically it usually bundles a still frame and a short clip in one file, making it heavier than an ordinary photo but lighter than a full video clip. This tool does not separate that category out — count it closer to a short video clip to be safe.

Yes, the photos stay on the phone as normal. The only risk is that if the phone is lost or breaks before you get home, anything not yet backed up goes with it. Weigh that risk against the convenience yourself.

Uploading many files at once keeps the radio and processor working hard continuously, especially when a large backlog backs up all at once. Setting it to back up in smaller batches over time, instead of letting a backlog build, eases this.

This tool calculates only for photos and clips shot on the phone itself. If you transfer photos in from a separate camera and back those up too, count that volume separately, since it sits outside this formula's assumptions.