The current chat uploader accepts files up to 20 MB each.
Supported chat upload types
Images: JPEG, PNG, GIF, and WEBP
Documents: PDF, DOC, DOCX, XLS, XLSX, CSV, TXT, PPT, and PPTX
Unsupported file types are rejected at upload time. Standard chat uploads do not currently include video files or arbitrary archives.
Upload availability still depends on your current access level and on whether the selected model supports attachments.