WMZ to OTB Converter

Convert WMZ to OTB — simple online tool

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Fully Browser-Based

No software to install, no plugins required. Open Convertio in any browser and convert WMZ to OTB immediately.

No Account Needed

No account creation required for basic conversions. Go from WMZ to OTB in seconds without any signup steps.

Quality Output

Get excellent OTB output from your WMZ source. The conversion engine maximizes on-the-air bitmap quality.

How to convert WMZ to OTB

1

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

2

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

3

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

About formats

WMZ is a compressed variant of the Windows Metafile (WMF) format, introduced by Microsoft with Office 2000 in 1999. A WMZ file is simply a WMF file compressed using the gzip algorithm (RFC 1952), reducing the file size for more efficient storage and embedding within Office documents, web pages, and other containers. The underlying WMF format stores vector graphics as a sequence of GDI (Graphics Device Interface) function calls — commands that draw lines, curves, polygons, text, and bitmaps — recorded in a device-independent format that can be replayed at any resolution. WMZ preserves this vector nature: when decompressed, the file produces a standard WMF that renders through the Windows GDI subsystem using the same drawing primitives as on-screen display, ensuring visual fidelity across different output devices and resolutions. WMZ files are commonly found embedded in Microsoft Office documents (Word, Excel, PowerPoint), HTML email messages generated by Outlook, and web content produced by Office's Save as Web Page feature. The format is also used for clip art and template graphics distributed with Office installations. One advantage is space efficiency: gzip compression typically reduces WMF file sizes by 60-80%, meaningful when many small graphics are embedded in a single document or web page. The format's deep integration with the Microsoft Office ecosystem is another practical strength — WMZ graphics render natively in all Office applications without additional software, and can be extracted, decompressed, and converted using tools like LibreOffice, ImageMagick, Inkscape, and standard gzip utilities.
Developer: Microsoft
Initial release: 1999
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

Frequently Asked Questions

Why convert WMZ to OTB?

Converting WMZ to OTB lets you extract vector graphics from Office documents into standard image formats — OTB is widely recognized and easy to share.

How do I open OTB files?

OTB files open in mobile device tools — widely supported across Windows, macOS, and Linux platforms.

Is WMZ to OTB conversion accurate?

Accuracy is a priority. The WMZ data is carefully decoded and re-encoded as OTB to maintain faithful output.

What platforms support this conversion?

Convertio works in any modern browser — Chrome, Firefox, Safari, Edge — on Windows, macOS, Linux, and mobile.

Does the conversion happen on my device?

No — conversion runs on Convertio servers. Your device handles only the upload and download, not the processing.

Can I convert multiple WMZ files at once?

Multiple WMZ files can be queued for conversion at the same time — each produces a separate OTB file.