I run a youtube channel and I want to start a challenge in my next video. What I'd like to do is hide a single image in the video at a random point. The idea is, unless you know what your looking for, you have to go through frame by frame to find the image. The first person to find it will win a prize. I use FCP7 and I've put an image into a single frame in the middle of my video, because thats what I was told to do. However two things, one, on play back the image is obvious and two, ive seen plenty of videos where you have to go frame by frame to find the image, hence where i got the idea. Can someone explain to me what i need to do to hide this image?