This website is fantastic, you can upload or point it at pictures hosted on the net and it removes the background, it's by no means perfect but for a quick and easy option it's pretty much unbeatable 

www.remove.bg



These are a low res shots from an image search, it took a couple of seconds to output.







In summary,

Someone mentioned it at work and I thought yeah that will be a total gimmick but it does actually work surprisingly well