Why are pictures not loading on my phone?

Question

Images

When I look at the site from my phone, a couple of pictures in the slider do not load, and there is no such problem on the computer, what could be the jamb? I wrote the slider myself. I tried to throw it into the sandbox, but it didn’t quite work out, because there is an array with pictures in the code, but I don’t know how to transfer them to the sandbox .
Let me know if you can solve the problem.