HRZ to MNG Converter

Switch from HRZ to MNG seamlessly online

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Format Bridge

Go from specialized HRZ (amateur radio slow-scan television) to universally supported MNG — making your data accessible to anyone without niche software.

Browser-Based Tool

No downloads or installations needed — open the converter in your browser and convert HRZ to MNG instantly from anywhere.

Remote Processing

The heavy lifting of HRZ to MNG conversion happens on cloud servers — your computer or phone stays fast and unaffected.

How to convert HRZ to MNG

1

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

2

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

3

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

About formats

HRZ is a simple raster image format associated with slow-scan television (SSTV), a method of transmitting still images over radio frequencies used by amateur radio operators since the late 1950s when Copthorne Macdonald pioneered the technology. HRZ files store images at a fixed resolution of 256x240 pixels in raw RGB format, with each pixel represented as three bytes (red, green, blue) at 8 bits per channel, producing uncompressed files of exactly 184,320 bytes. The format has no header, no metadata, and no compression — the file is simply a sequential dump of raw pixel data in row-major order. This extreme simplicity reflects the format's origins in the amateur radio community, where SSTV images are transmitted as audio tones encoding luminance and chrominance values over narrow-bandwidth HF (shortwave) radio channels. The fixed 256x240 resolution corresponds to common SSTV transmission modes, and HRZ files serve as the digital capture or storage medium for received SSTV transmissions. One advantage is the format's zero-overhead structure: with no parsing, decompression, or metadata processing required, HRZ files can be read by any program capable of reading raw pixel data with known dimensions — a single function call in virtually any programming language. The format's connection to amateur radio SSTV culture is another notable aspect: HRZ files document a unique form of image communication where operators transmit photographs over thousands of miles using nothing but radio waves and audio encoding, a practice that continues today alongside digital modes. HRZ files can be opened by ImageMagick, GIMP, and specialized SSTV software.
Developer: SSTV Community
Initial release: 1985
MNG (Multiple-image Network Graphics) is an animation and multiple-image format designed as the animated counterpart to PNG, with its specification reaching version 1.0 on January 31, 2001. Developed by Glenn Randers-Pehrson and members of the PNG development community, MNG extends PNG's capabilities with support for frame-based animation sequences, slide shows, complex sprite overlays, and JNG (JPEG Network Graphics) frames for lossy compression of photographic content within the same container. An MNG file consists of a series of chunks (following PNG's chunk-based architecture): MHDR and MEND chunks bookend the datastream, with embedded PNG or JNG images as individual frames and control chunks (DEFI, FRAM, LOOP, ENDL, TERM, BACK, BASI, CLON, PAST, DISC, SHOW) directing playback timing, looping behavior, layer compositing, and memory management. The format supports both full-frame replacement and delta (difference) updates for efficient encoding of animations with static backgrounds, as well as object-based animation where sprites are defined once and repositioned across frames. One advantage is technical sophistication: MNG provides a level of animation control that GIF and APNG cannot match — frame-accurate timing, nested loops, conditional branches, interframe compression, and mixed lossy/lossless content within a single animation. The PNG-based foundation ensures lossless quality with full alpha transparency for each frame. MNG is supported by ImageMagick, GIMP, and various media players, though browser support was limited, which led to APNG's emergence as a simpler alternative for web animation.
Initial release: January 31, 2001

Frequently Asked Questions

Why convert HRZ to MNG?

Most people lack software for HRZ. Converting to MNG ensures your SSTV images are viewable everywhere — from phones to desktops.

What programs open MNG?

Open MNG with standard tools like Windows Photos, Preview on macOS, GIMP, Photoshop, or any web browser — no special software needed.

Does the conversion preserve quality?

The converter retains maximum fidelity during the HRZ to MNG transformation. Any differences stem from the output format's own characteristics.

Can I convert on a phone or tablet?

Absolutely — the online converter works in mobile browsers just as well as on desktop. No app installation is required at all.

Can I convert multiple HRZ images at once?

Yes — upload several HRZ images in one session and convert them all to MNG simultaneously. Batch processing saves significant time.

Do I need HRZ software installed?

No — the converter processes HRZ entirely in the cloud. You do not need any amateur radio slow-scan television software on your device to convert.