For File Upload items in the activity builder, there should be a way to limit file types and sizes. For example, some assignments specify uploading handwritten responses, and limiting file types to jpg would be useful. this would also be needed to prevent uploading of ios or Android file types that can't be read by instructors' operating systems.

When students attempt to upload very large files, their submission cannot be saved, resulting in a permanent error that prevents both student and teacher from viewing the activity submission.