Image MIME Reference
BTIF
Bank Telecommunications Image Format
image/prs.btif
VS
Group 3 Fax Image
image/g3fax
G3-Fax
A complete technical comparison of Bank Telecommunications Image Format and Group 3 Fax Image — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | BTIF | G3-Fax |
|---|---|---|
| Transparency (Alpha) | ✕ No | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | ✕ No | ✕ No |
| EXIF Metadata | ✕ No | ✕ No |
| ICC Color Profile | ✕ No | ✕ No |
Bank Telecommunications Image Format
image/prs.btif
Extension
.btif.btf
Container
Proprietary Check Image Container
Compression
Lossy (JPEG-based) / Lossless (TIFF-based)
Algorithm
JPEGTIFF-variant
Color Depth
1-bit (B&W), 8-bit (Grayscale)
Developed by
NationsBank (Bank of America) / Ben Simon
Released
1998
Magic Bytes
Unknown (Proprietary container)
Group 3 Fax Image
image/g3fax
Extension
.g3
Container
Raw Bitstream
Compression
Lossless (CCITT Group 3)
Algorithm
CCITT Group 3 (Modified Huffman / READ)
Color Depth
1-bit (Monochrome)
Developed by
CCITT (now ITU-T) / IETF
Released
1980
Magic Bytes
None (Raw Bitstream)
Browser Support Comparison
| Browser | BTIF | G3-Fax |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
BTIF
BTIF Strengths
- Allowed early digital archiving and web-based transmission of cleared bank checks
- Encapsulated both image data and ASCII transaction metadata in a single file
Limitations
- Completely proprietary and obsolete format
- Lacks native support in modern operating systems and image viewers
- Requires legacy plugins or specialized bio-format readers (like ImageC) to decode
G3-Fax
G3-Fax Strengths
- Extremely efficient compression for 1-bit black-and-white text and line art
- Standardized via RFC 1494 for email and internet fax transmission
- Low bandwidth requirements
Limitations
- Raw format lacks metadata (such as image width and resolution), requiring out-of-band information to decode accurately
- Strictly limited to 1-bit monochrome imagery
- Zero native web browser support
When to choose which format
BTIF
Use BTIF when…
- Bank Check Archiving (Legacy)
- Financial Transaction Records
G3-Fax
Use G3-Fax when…
- Telefacsimile (Fax) Transmission
- Internet Fax (T.37)
- Document Archiving
- Telephony Systems