Bad link requests

I have run speed test on GT Metrix and Google dev. They have both said there are some bad link requests for some image files.

I’ve looked in the media library but I can’t see the files there.

Where can I find them?

They all take this format https://domain.com/data/2016/10/image_7_red.png but I don’t know where to find the data folder.

Do I need to go into the host file manager?
This is the site https://bit.ly/2yFGnGz

And here is one of the bad request links https://bit.ly/2xTGLx0.

Thanks

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