`ac mime <file> ["caption"]` posts a file as an opening post on mime.ac, signed with ~/.ac-token, on its MIME type's board, and prints the thread address. Aesel's media list offers the same, confirmed before it posts. The client checks size and type first; files over 8 MiB are refused until opening posts can carry a storage URL. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>