You can find out more about the AWS S3 issue here.
After further research, the issue not only affected image content in courses – it also affected student’s ability to upload or access files in courses – including but not limited to, access to course syllabi, files in course Resources, upload of assignments as attachments, entry of forum and blog posts and and submission of assignments. Other areas may have also been affected as well.
While it’s expected that the issue will be resolved soon, instructors are asked to use discretion when accepting assignments and other grade-impacting tasks which rely on electronic submission via Sakai. While not preferable, some instructors may decide to correspond with students via standard email about changes/adjustments to assignment submission processes due to the AWS issue, including extending the due or accept until date(s). Instructor’s ability to access student submissions, files and related gradable digital content is also an issue in some cases.
Students are encouraged to create and author content using an offline editor (such as in Word or Pages) and save their work so they have a back up and can potentially submit their work later or using a different means.