OTB to PGM Converter

Seamless OTB to PGM image conversion, done in the cloud

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Cross-Platform Access

Whether you are on a desktop, tablet, or phone — convert OTB to PGM from any device with a modern web browser.

Reliable Conversion

Convertio handles the OTB to PGM transformation accurately, preserving your image content while delivering a widely compatible output.

Simple Interface

Three steps to convert: upload your OTB, select PGM, and download. The clean interface makes the process intuitive even for first-time users.

How to convert OTB to PGM

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose pgm or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your pgm file right afterwards

About formats

OTB (Over-the-Air Bitmap) is a monochrome image format developed by Nokia as part of their Smart Messaging specification in 1997, designed for transmitting small graphics — operator logos, group graphics, and picture messages — to Nokia mobile phones via SMS. OTB files contain 1-bit (black and white) images at small fixed resolutions, typically 72x14 pixels for operator logos and 72x28 pixels for group graphics, encoded in a compact binary format suitable for embedding within the payload of SMS text messages. The format uses a simple structure: a header byte indicating whether the image is an operator logo or group graphic, width and height values, and the raw bitmap data where each bit represents one pixel packed eight per byte. The extremely tight format — designed to fit within a single SMS message (140 bytes maximum payload, shared with addressing overhead) — reflects the severe constraints of mobile communication in the late 1990s. Nokia's Smart Messaging system was one of the first commercial implementations of rich content delivery to mobile phones, and OTB images represented the entire visual content capability of Nokia handsets before MMS and mobile data browsing arrived. One advantage is the format's historical role as a pioneer of mobile visual messaging: OTB images were among the first graphics that ordinary consumers could send to each other's phones, predating MMS, camera phones, and smartphones by nearly a decade. The format's minimal footprint is another characteristic — entire images fit in a few dozen bytes, reflecting an era of extreme bandwidth constraints. OTB files are supported by ImageMagick, various Nokia phone management tools, and specialty mobile format utilities.
Developer: Nokia
Initial release: 1997
PGM (Portable Graymap) is the grayscale member of the Netpbm image format family, created by Jef Poskanzer in 1988 as part of the Pbmplus toolkit for Unix systems. PGM stores single-channel intensity images where each pixel holds a gray value from 0 (black) to a user-specified maximum (typically 255 for 8-bit or 65535 for 16-bit). The format exists in ASCII (magic number P2), where pixel values are written as decimal text numbers separated by whitespace, and binary (magic number P5), where values are stored as raw bytes. Both variants begin with a header specifying the magic number, width, height, and maximum gray value. PGM was designed as the grayscale intermediate in Netpbm's convert-process-convert pipeline philosophy: source images from any format are converted to PGM, processed using Netpbm's extensive command-line tool library, then converted to the target format. One advantage is format transparency — the ASCII variant makes image data directly readable by humans and trivially processable by text tools like awk and grep, invaluable for debugging and education. The scientific and computer vision community's adoption is another strength: PGM's straightforward single-channel representation makes it a natural format for image analysis algorithms, and many academic papers and course materials use PGM examples. The format is supported by ImageMagick, GIMP, and countless image processing libraries, and remains standard input for many research tools and benchmarks.
Developer: Jef Poskanzer
Initial release: 1988

Frequently Asked Questions

What is the reason to convert OTB to PGM?

OTB is tied to Nokia mobile phones. Switching to PGM gives you grayscale image format from the Netpbm toolkit and broad support across platforms, browsers, and devices.

How do I open a PGM file?

Software that handles PGM includes GIMP, ImageMagick, IrfanView, XnView — giving you options on every major operating system.

Is OTB to PGM conversion free?

Yes — Convertio offers free OTB to PGM conversion. Premium options exist for users who need more capacity or faster processing speeds.

Does this converter work on mobile devices?

It works on any device with a web browser. Whether you are on Android, iOS, Windows, or macOS — OTB to PGM conversion is fully supported.

Can I convert multiple OTB files to PGM at once?

Absolutely. Batch upload your OTB images and convert them all to PGM in a single pass — no need to repeat the process for each file.

What exactly is the OTB format?

OTB (Over-The-Air bitmap format for early Nokia phones) originated in Nokia mobile phones. It has very limited modern application support but can be converted to modern formats on Convertio.