FFMPEG
Overlay Image on Video
ffmpeg -i INPUT.mp4 -i INPUT.jpg -filter_complex "[0:v][1:v] overlay=0:enable='between(t,0,1)'" OUTPUT.mp4
The option (t,0,1) denotes how long the image stays on screen in SECONDS. In this case, 0,1 means to have the image show up at the 0th second and be gone by the 1st second. So one second. If we siad (t,0,0.5) the image would load up at the beginning and go away after half a second. To make it go to the end, just put as many seconds as it takes to finish the video.