Images not displaying on D3 map on Github Page project

Hi I am trying to publish my first web project - a D3 map that shows a journey with mouse events to show tooltips with images and data relating to the voyage here.Only some of my images show up on GitHub pages although all have been added to the project https://github.com/SallyFl/OskarSpeckMapApril2018/tree/gh-pages. I get that they are probably too big having seen the message Diff not rendered and Binary file not shown but I don’t really understand what this means. I tried resizing them to smaller images but still only a few are showing up. Should I try resizing them even smaller and if so what is the maximum size? Or is this not the best place to publish my project?

I am a completely new user of this site and also a newbie so any advice, preferably simple and not too technical, would be very welcome.

It looks like the repository you linked to is private and the website is showing as a 404. If you’re still looking for help with this, let me know where to find it and I’ll take a look. (Though I haven’t used D3 very much, so I might have to fumble around a bit.)