How to create a x264 (mp4) video with the smallest size using ffmpeg that has just 1 image through entire video?
ffmpeg will do it for you - https://stackoverflow.com/questions/5887311/ffmpeg-1-image-1-audio-file-1-video

If you want to provide good seeking ability, you will need to provide key frames at certain intervals in the encoding, which will increase the size of the video. The codec will encode the whole frame at each of the keyframes but greatly compress the intervening frames. By playing around with the value of the key frame interval, you can arrive at a good compromise for your needs.