Author needs to figure out a better way of doing screencapture. Using an image that might _actually_ induce seizures isn't a very good first impression.
Why does he need to make a good impression? look at the code and make your determination - build it and make a pull request with your improved video. This is the spirit of Github: he may be an awesome coder but weak in video production - fork and collaborate.
You seem to be of the mindset that "Open Source" means "other people will be eager to contribute". That's not necessarily the case. If you want people to contribute, you need to give them a reason to do so. People like contributing to high-quality projects. If the first impression of your project indicates a lack of quality, this will deter people from looking any further.