Hello, LambdaSP,
We suppose that the situation is independent of our theme.
1/ Given that your images are loading from a CDN, we suggest that you first disable CDN and check if that resolves the issue.
2/ How often does this occur? What preceded it?
3/ Could you please get in touch with the hosting provider and check if there have been any breaches to your website?
Kind Regards,
8theme team