Images not loading

I’m not sure where the issue lies but for about 2 weeks now this has been occurring and only on sites that have WordPress 4.0.1. At times, the photos won’t load and I get an error. My permissions are set accordingly so I know that is not the problem. The photos are large but I’ve never had problem before with large photos. Anyone else having issues on this support forum? I have read about it on other forums but no solutions as to how to fix the problem. It might be a wordpress issue. Any thoughts?

Thanks
Carla