Hi,
I am having similar problems with my images. I added the images to my blog post but after I save the post as draft and I go back to editing the post again, some of the images doesn’t load and just show up as rectangle boxes with the alt text. I deleted the images that were having problems and uploaded them again, but the same thing happens. Everything is fine straight after upload, but after I save the post as draft and go back to edit the post later, the same images does not show up.
I have tried deactivating all my plugins, I have deleted and re-uploaded all the images, but the problem persists.