Can it remove something large?

On a simple background (sky, wall, ground) yes, even large things go cleanly. On busy backgrounds, work in several smaller passes.

Is the photo uploaded?

No. The erasing runs on your computer; press "Network" in the bar to see for yourself.

Someone walked into your landscape shot, or a stray object sits in your product photo. Paint over it and the background fills in naturally.

Drop the photo on "Remove object". The first time, the eraser model is fetched once into this browser.
Paint over the person or object, a little larger than it is. Include the shadow for a natural result.
Press "Erase". The area fills in from its surroundings. Paint again over anything that still shows.
Save. For social media, hand it to "Compress" to make it lighter.

Can it remove something large?: On a simple background (sky, wall, ground) yes, even large things go cleanly. On busy backgrounds, work in several smaller passes.
Is the photo uploaded?: No. The erasing runs on your computer; press "Network" in the bar to see for yourself.

Pictures are never sent anywhere; everything runs in this browser.