One of the bloggers in our multisite WordPress network reported the following:
I am unable to determine what is causing the images inserted in our WordPress site blogs.princeton.edu/etc to no longer be visible a random amount of time after they've been inserted in a post. The image will be visible in the post for a week or two after insertion, and then the next time the post loads all that's visible is either a file name which is also an active link that opens the image file (Firefox), or a small question mark inside a blue square, inside a small rectangle box (Safari), or a square broken picture image inside a rectangle box. It's also generally a struggle to find an image that will be visible in a post after upload, even though it's visible in the Media Library.
She gave a couple of examples, and I think that I have narrowed down the problem to the month numbers in the image URLs. In the following two posts, the broken images are in the media library, and they show up in the edit screen. However, the images on the live pages are broken.
Both posts were authored in March (03). However, they were both revised in April (04). The original images have /2014/03/ in the URL. The derivative images have /2014/04/ in the URL.
On the live site, when you try to access the images directly with a right-click, you get the following error message:
We cannot complete this request, remote data was invalid
Notice the date in the Photon-generated image URLs
Interestingly, when I manually edit the URLs back to March, the images load as expected.
This is the first time that I have encountered this issue. I am not sure how easily reproducible it is. I suppose editing a post from a previous month, to see if the URLs from the derivative images change to the current month might work.
We are using WordPress 3.8.1 and Jetpack 2.9.2.