{"id":"image-ief","mimeType":"image/ief","name":"Image Exchange Format","shortName":"IEF","category":"Legacy \u0026 Telecommunications","extensions":[".ief"],"description":"The Image Exchange Format (IEF) is a legacy image format defined in RFC 1314. Developed in the early 1990s, it provided a standardized way to transmit bi-level (black and white) fax-like images over the Internet, utilizing the TIFF Class B (TIFF-B) structure.","seo":{"title":"image/ief MIME Type | Complete Developer Reference \u0026 Magic Bytes","description":"Complete reference for the image/ief MIME type: magic bytes, software support, HTTP headers, developer snippets, and technical specifications for Image Exchange Format.","faqs":[{"question":"What is the magic byte for an IEF file?","answer":"Because the IEF standard is defined as a subset of the TIFF format (specifically TIFF-B), it utilizes standard TIFF magic bytes. A file will begin with either 49 49 2A 00 (little-endian) or 4D 4D 00 2A (big-endian)."},{"question":"Is image/ief still used?","answer":"No. The Image Exchange Format is considered completely obsolete. It has been superseded by more robust standards like TIFF-FX, standard multi-page TIFF, PDF, and PNG for document exchange."},{"question":"Can web browsers open IEF files?","answer":"No modern web browser supports the IEF format natively. It was designed for legacy internet fax gateways and requires specialized TIFF viewers or conversion to modern formats."}]},"index":{"compression":["Lossless (MH, MR, MMR)","Uncompressed"],"browserSupport":{"score":1,"label":"None"},"commonUses":["Legacy Fax Transmissions","Early Internet Gateways","Archival"]},"technical":{"magicBytes":{"hex":"49 49 2A 00 (Little-endian) / 4D 4D 00 2A (Big-endian)","ascii":"II*. / MM.*"},"container":"TIFF Class B (TIFF-B)","compressionAlgorithm":["MH","MR","MMR","Uncompressed"],"colorDepth":["1-bit (Monochrome)"],"transparency":false,"animation":false,"metadata":{"exif":false,"xmp":false,"iccProfile":false},"alphaChannel":false,"progressiveLoading":false,"hdrSupport":false},"history":{"developer":"IETF Network Fax Working Group","released":"1992","specification":"RFC 1314"},"browserSupport":{"chrome":false,"chromeVersion":"None","firefox":false,"firefoxVersion":"None","safari":false,"safariVersion":"None","edge":false,"edgeVersion":"None","internetExplorer":false},"softwareSupport":[{"name":"ImageMagick","logo":"image-magic.webp"},{"name":"JHOVE","logo":""},{"name":"XnView","logo":""},{"name":"Ghostscript","logo":""}],"conversion":{"convertTo":["tiff","png","jpeg"],"convertFrom":["tiff","fax-g3"]},"developer":{"httpHeaders":[{"header":"Content-Type","value":"image/ief"}],"htmlAccept":"image/ief, .ief","fileDetection":["Check for standard TIFF headers: 'II*\\0' (49 49 2A 00) or 'MM\\0*' (4D 4D 00 2A)","Parse the TIFF Image File Directories (IFD) to verify the image uses 1-bit monochrome sample depth (TIFF-B requirements)"]},"prosCons":{"pros":["Provided a standard method for exchanging bi-level fax images during the early days of the Internet","Supported multi-page documents","Leveraged the highly resilient and well-documented TIFF container"],"cons":["Completely obsolete and unsupported in modern computing environments","Strictly limited to 1-bit monochrome data, lacking color or grayscale capabilities","Magic bytes overlap completely with standard TIFF, making specific filetype detection difficult without parsing internal tags"]},"specifications":{"url":"https://datatracker.ietf.org/doc/html/rfc1314","rfc":"RFC 1314","mimeAliases":["image/tiff"]},"developerSnippets":{"python":"import magic\nprint(magic.from_file('document.ief', mime=True)) # Will typically resolve to 'image/tiff' due to the shared header","nodejs":"const FileType = require('file-type');\nconst type = await FileType.fromFile('document.ief');\nconsole.log(type?.mime); // Parsers will likely return 'image/tiff'","go":"import \"net/http\"\n// HTTP detection will fall back to standard TIFF\nif bytes.HasPrefix(buf, []byte{0x49, 0x49, 0x2A, 0x00}) || bytes.HasPrefix(buf, []byte{0x4D, 0x4D, 0x00, 0x2A}) {\n    fmt.Println(\"image/tiff (or image/ief)\")\n}","php":"$mime = mime_content_type('document.ief');\necho $mime; // Most likely outputs 'image/tiff'"},"relatedFormats":["tiff"]}