If you want to overlay an image on video, you can use ffmpeg command.
Suppose you want to overlay an logo image on bottom right of the video, run this command.
Code:
ffmpeg -i /path/of/video.avi -vf "movie=/path/of/image/logo.png [img]; [in][img] overlay=main_w-overlay_w-10:main_h-overlay_h-10" -vcodec libx264 /path/of/output/video.avi