WBMP

Wireless Bitmap

image/vnd.wap.wbmp Released 1999 · by WAP Forum (Now Open Mobile Alliance)

The image/vnd.wap.wbmp MIME type represents the Wireless Bitmap (WBMP) format, developed by the WAP Forum in the late 1990s. Designed explicitly for early mobile phones with constrained processing power, low bandwidth, and monochrome screens, WBMP is a highly simplified, 1-bit (black and white) uncompressed image format. It was a foundational component of the Wireless Application Protocol (WAP) ecosystem, enabling the very first wave of mobile web browsing. It has since been rendered entirely obsolete by the widespread adoption of color displays and modern formats like PNG, GIF, and JPEG on mobile devices.

Legacy & Mobile Production Ready

Technical Specifications

MIME Type

image/vnd.wap.wbmp

Extensions

.wbmp

Container

WBMP Type 0

Compression

Uncompressed

Algorithms

None

Color Depth

1-bit (Monochrome)

Metadata

None

Capabilities

Transparency

Animation

Progressive Loading

Alpha Channel

HDR Support

Official Specification

Aliases: image/wbmp

Magic Bytes & HTTP Headers

File Signature (Magic Bytes)

00 00

ASCII: \x00\x00

HTTP Headers

Content-Type: image/vnd.wap.wbmp

HTML Accept Attribute

accept="image/vnd.wap.wbmp, .wbmp"

Browser Support Matrix

Browser	Status	Min Version
Chrome	Not Supported	—
Firefox	Not Supported	—
Safari	Not Supported	—
Edge	Not Supported	—
Internet Explorer	Not Supported	Legacy

Advantages & Limitations

Advantages

Extremely low processing overhead made it perfectly suited for the ultra-low-power CPUs of late 1990s mobile devices
Tightly integrated into the WML (Wireless Markup Language) stack, enabling the first functional mobile internet experiences

Limitations

Completely obsolete and lacks support in modern operating systems and browsers
Limited entirely to 1-bit black and white (0 for black, 1 for white) with zero support for grayscale, color, or transparency
The lack of a strong file header signature makes automated MIME type detection highly unreliable

Developer Code Snippets

import magic
# Libmagic may struggle to accurately identify WBMP files due to the weak '00 00' header.
print(magic.from_file('icon.wbmp', mime=True))

const mime = require('mime');
// JS MIME libraries generally map .wbmp to image/vnd.wap.wbmp based on the extension
console.log(mime.getType('icon.wbmp')); // Outputs 'image/vnd.wap.wbmp'

import (
    "bytes"
    "net/http"
)
// http.DetectContentType will not reliably identify WBMP files. It will likely return 'application/octet-stream'.

// PHP's GD extension famously retained legacy WBMP support for decades
$mime = mime_content_type('icon.wbmp');
// You can also create them dynamically:
// $im = imagecreate(20, 20);
// imagewbmp($im, 'icon.wbmp');

File Detection Steps

How to programmatically detect a image/vnd.wap.wbmp file by reading its raw bytes:

1 The WBMP format lacks a strong, unique magic string. A standard Type 0 WBMP file simply begins with two 0x00 bytes (TypeField = 0, FixHeaderField = 0).
2 Because 00 00 is extremely common at the start of various binary formats, relying strictly on magic bytes for WBMP often results in false positives.
3 Robust parsers must read the subsequent multi-byte integer fields (representing image width and height) and validate that the remaining file size perfectly matches the calculated bitwise dimensions.

Software Support

ImageMagick

GIMP

P

PHP GD Library

Conversion Tools

Share & Embed

Markdown Badge

[![WBMP Format](https://freewebptojpg.com/mime/image/wbmp/badge.svg)](https://freewebptojpg.com/mime/image/wbmp)

Interactive iframe Widget

<iframe src="https://freewebptojpg.com/mime/image/wbmp/embed" width="100%" height="280" style="border:1px solid #cbd5e1;border-radius:8px;" title="WBMP Specs"></iframe>

JSON API

All data on this page is available as a free, open JSON API. Use it in your project, documentation, or tooling.

GET https://freewebptojpg.com/mime/image/wbmp.json Open JSON

Free to use

No auth required

CORS enabled

Use from any domain

Cached 24h

Cache-Control headers set

Frequently Asked Questions

What is a WBMP file?

A WBMP (Wireless Bitmap) is a legacy 1-bit monochrome image format created for early WAP-enabled mobile phones (like late-1990s Nokia and Ericsson models). It was used to display simple black-and-white icons and logos over slow cellular networks.

Can modern web browsers display WBMP images?

No. Modern desktop and mobile browsers do not support rendering WBMP files. They were completely replaced by standard formats like GIF, PNG, and JPEG as mobile screens evolved to support color.

How do I convert a WBMP to a modern format?

Standard command-line image processing tools like ImageMagick, and server-side libraries like PHP's GD extension, still retain legacy support for decoding and converting WBMP files into standard PNGs or JPEGs.