A camera that submits like a file input
A device produces a Blob; a form expects a FileList, and FileList is read-only. The one constructible path, and what it saves you on the server.
CORS for a write surface
Allow-Origin star is fine for a public feed and catastrophic for a write endpoint. A per-form allow-list, exact origin matching, and the preflight trap.
Sixteen operators, six actions, two implementations
Conditional form logic in the browser is presentation, not validation. Keeping show, enable and require independent — and the half that must exist twice.