It's super easy to add filters, adjust levels, and crop images using the default photo editor on your smartphone, but there's rarely any built-in tool for removing the background in a photo. A third-party app can help isolate people and objects in your pictures, and we've found a free one that's easy to use, works with high-resolution images, and is available for Android, iOS, iPadOS, and the web. There are lots of background remover apps out there, but you'd be lucky to find one that doesn't...