YouTube is preparing to roll out a new thumbnail testing feature to creators, which means you’ll probably notice thumbnails on videos changing more often. Thumbnails are the first way in which a creator can advertise a video on YouTube and, often, creators will swap out the thumbnail after the video was first uploaded to help it appeal to more viewers over time. Now, YouTube is making that process a whole lot easier. Announced this week, YouTube will start to roll out “Thumbnail Test & Compare” ...