Hi Dalin,
Thanks for bringing this up. The same behavior has been reported by several other customers and we have found that it is occurring due to a technical problem on the end of our image hosting provider, Amazon S3. They are investigating the issue and have posted an acknowledgment of the problem on the following page:
http://status.aws.amazon.com/The service is described as "Amazon Simple Storage Service (US Standard)" on that status page and the error message currently says "Increase in error rates". They will be updating that page when the issue is resolved and your images should then be visible once again.
We apologize for any inconveniences this issue is causing.
-Mike