What is WBMP? Wireless Bitmap Format Explained
A monochrome 1-bit image format created by the WAP Forum for early mobile and WAP devices.
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What is WBMP?
WBMP, the Wireless Application Protocol Bitmap Format (Wireless Bitmap), is a monochrome raster image format defined by the WAP Forum for early mobile devices such as WAP-enabled phones and PDAs. It was designed to deliver simple graphics over slow, bandwidth-limited wireless networks.
A WBMP image is strictly 1-bit, with each pixel being either black or white, and uses a compact header recording a type field followed by the width and height. Because early wireless devices had limited processing power, the format is uncompressed, keeping decoding fast and file sizes small thanks to its minimal structure.
How WBMP Works
A WBMP file uses an extremely compact header: a type field (only type 0 is defined), a fixed-header byte for extension flags, and then the image width and height encoded as multi-byte integers using a variable-length scheme.[1] Pixel data follows as a 1-bit-per-pixel bitmap, packed eight pixels to a byte and padded to byte boundaries at the end of each row, with no compression applied.[1]
History and Purpose
The WAP Forum defined WBMP as part of the Wireless Application Protocol stack so that early mobile phones and PDAs could display simple graphics over slow wireless links.[1] It is served under the image/vnd.wap.wbmp media type and was typically embedded in WML pages alongside WAP browsing.[2]
WBMP vs Modern Formats
Restricted to a single black-and-white bit per pixel and lacking any compression, WBMP traded image quality for minimal decoder complexity, an appropriate compromise for the constrained devices of its era.[3] With the move to faster mobile networks and capable smartphone browsers supporting GIF, PNG, and JPEG, WBMP fell out of use and is now effectively obsolete.[3]
MKV Technical Specifications
WBMP vs Other Image Formats
| Feature | WBMP | PNG | GIF |
|---|---|---|---|
| Type | Raster | Raster | Raster |
| Color depth | 1-bit (monochrome)[1] | Up to 16-bit | 8-bit palette |
| Compression | None[1] | Lossless | Lossless (LZW) |
| Transparency | No | Yes | Yes (1-bit) |
| Origin | WAP mobile[1] | Web standard | Web standard |
| Best for | Legacy WAP phones[3] | Web graphics | Simple animation |
WBMP was designed for monochrome display on early WAP mobile devices and is now largely obsolete next to PNG and GIF.
Advantages & Disadvantages
Advantages
A minimal header and 1-bit pixels keep WBMP files tiny, which suited slow early mobile networks.
The uncompressed format avoided decompression overhead on low-powered wireless devices.
Its compact, well-defined header makes WBMP easy to generate and parse.
It was tailored to display images within WML pages on early mobile browsers.
Disadvantages
WBMP supports just 1-bit black-and-white images, with no grayscale or color.
With the decline of WAP and the rise of capable smartphones, WBMP is rarely used today.
Larger monochrome images grow proportionally in size because the format does not compress pixel data.
Common Use Cases
WBMP was used for lightweight graphics on early mobile and WAP devices.
WAP page graphics | FileFormer
WBMP images were embedded in WML pages displayed by early mobile browsers.
Early mobile content | FileFormer
Simple logos and icons were delivered to feature phones as WBMP files.
Legacy mobile support | FileFormer
The format is encountered mainly when handling content from the WAP era.
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Try Image Converter FreeFrequently Asked Questions
What does WBMP stand for?
WBMP stands for Wireless Application Protocol Bitmap Format, commonly called Wireless Bitmap.
What kind of images can WBMP store?
Only 1-bit monochrome images, where each pixel is either black or white. It does not support grayscale or color.
Who created the WBMP format?
It was defined by the WAP Forum as part of the Wireless Application Protocol for early mobile devices.
What is the MIME type for WBMP?
The MIME type is image/vnd.wap.wbmp and the file extension is .wbmp.
Is WBMP still used?
Rarely. It was tied to the WAP era of early mobile phones and has been largely replaced by modern image formats on smartphones.