Images occasionally not showing on website

Hi, I have a problem with my website and I need help.
So, the problem is that, from time to time, images on the website won’t load (it lasts for few hours and between computers).
I have noticed that only images from “/Images/Post” won’t load, rest loads normal.
The images are loaded by using links from external .js file.
Earlier there weren’t any problems with that, and since then I haven’t really change code for loading the images so I doubt that this is causing it.
Is there any way of fixing this?