OTB to PNG Converter

Quick OTB to PNG image conversion — fully browser-based

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Format Upgrade

Move from early Nokia mobile eran OTB to the modern PNG format — enjoy lossless compression with transparency support and broad software compatibility.

Simple Interface

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

Privacy Protected

Your OTB files are deleted immediately after conversion to PNG. Converted files are automatically removed from servers within 24 hours.

How to convert OTB to PNG

1

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

2

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

3

Let the file convert and you can download your png 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
PNG (Portable Network Graphics) is a lossless raster image format developed by the PNG Development Group and published as a W3C Recommendation on October 1, 1996, created as a patent-free replacement for GIF after the Unisys LZW patent controversy. PNG uses a two-stage compression pipeline: a prediction filter selects the optimal per-row preprocessing (none, sub, up, average, or Paeth), then DEFLATE compression encodes the filtered data. The format supports rich color modes — 1/2/4/8/16-bit grayscale, 8/16-bit per channel true color, and indexed color with palettes up to 256 entries — all with optional alpha transparency ranging from a single transparent color to a full per-pixel alpha channel with 256 or 65536 levels. PNG also stores gamma correction, ICC color profiles, text metadata, and suggested background color. One advantage is lossless compression with transparency — PNG preserves every pixel exactly while supporting smooth semi-transparent edges, making it the standard format for web graphics, UI elements, logos, screenshots, and any image where artifacts or color shifts are unacceptable. Universal support is another core strength: every web browser, operating system, image editor, and programming library handles PNG natively. The format has proven remarkably durable — after nearly three decades, PNG remains the default lossless web image format. While newer formats like WebP and AVIF offer better compression, PNG's combination of lossless quality, full transparency, and absolute ubiquity keeps it indispensable.
Initial release: October 1, 1996

Frequently Asked Questions

Why convert OTB to PNG?

Few modern tools handle OTB natively. PNG provides lossless compression with transparency support, making it widely recognized across operating systems and applications.

What programs open PNG files?

Open PNG using any web browser, Photoshop, GIMP, Paint, Preview. Cross-platform support means you can access these files on virtually any system.

What exactly is the OTB format?

The OTB format is an Over-The-Air bitmap format for early Nokia phones, rooted in Nokia mobile phones. Modern software rarely supports it natively, making conversion essential.

Is OTB to PNG conversion free?

You can convert OTB to PNG for free on Convertio. Premium plans are available if you need higher throughput or larger file allowances.

Does this converter work on mobile devices?

Yes — Convertio runs entirely in the browser. You can convert OTB to PNG on phones, tablets, or desktops without installing anything.

Are my uploaded files kept private?

Yes — your OTB files are deleted immediately after processing. The resulting PNG files are also removed from servers within 24 hours.

OTB to PNG Quality Rating

3.8 (6 votes)
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