Remove.bg is a free service that removes background images from photos in five seconds or less. The site employs a clever API that determines and separates foreground from the discarded background. The only caveat at this time is that it only works on photos with people or faces.
You don’t have to manually select the background/foreground layers to separate them – just select your image and instantly download the result image with the background removed! …Our AI is trained to detect persons as foreground and everything else as background. That’s why it only works if there is at least one person in the image.
via Doctor Popular