PICON to G4 Converter

Change PICON images to G4 — no downloads, works online

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Modern Format Output

G4 provides high-speed fax compression encoding — a significant upgrade over the legacy PICON format for everyday image use and sharing.

Simple Interface

Three steps to convert: upload your PICON, select G4, and download. The clean interface makes the process intuitive even for first-time users.

Cross-Platform Access

Whether you are on a desktop, tablet, or phone — convert PICON to G4 from any device with a modern web browser.

How to convert PICON to G4

1

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

2

Choose g4 or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your g4 file right afterwards

About formats

PICON (Personal Icon) is a small-format image type used in the X Window System ecosystem, developed by Steve Kinzler at Indiana University around 1990 as part of the picons (personal icons) database project. Picons are small, typically 48x48 pixel, color images used as visual identifiers for people, organizations, domains, and Usenet newsgroups in Unix mail readers, news readers, and other communication tools. The picon format is essentially an XPM (X PixMap) image stored with specific naming conventions and directory structures that allow software to look up the appropriate icon based on email address, domain name, or newsgroup name. The picons database organized thousands of these small images in a hierarchical directory structure keyed by domain name components (e.g., faces/com/example/user.xpm), enabling mail clients like exmstrstrstr and faces to automatically display a sender's photo or organizational logo alongside their messages. The system predated the modern concept of contact photos and avatars by more than a decade. One advantage is the system's pioneering role in visual identity for electronic communication: picons introduced the idea that email and Usenet messages should display a visual representation of the sender — a concept that eventually became standard in every modern email client, messaging app, and social media platform. The XPM-based format ensures that picons are displayable on any system with X Window libraries. Picon images are supported by ImageMagick, GIMP, and X Window display utilities, and the historical picons database remains archived online at Indiana University.
Developer: Steve Kinzler
Initial release: 1990
G4 is a monochrome image format based on the ITU-T Group 4 facsimile coding standard (Recommendation T.6), ratified by the CCITT in 1984 as an improvement over Group 3 for use on error-free digital networks like ISDN rather than analog telephone lines. G4 files contain 1-bit image data compressed using exclusively two-dimensional Modified Modified READ (MMR) coding, where each scanline is encoded as a set of differences (changing elements) relative to the line above it. By eliminating the one-dimensional coding fallback and the end-of-line synchronization markers required by Group 3, G4 achieves 20-50% better compression ratios on typical document pages while producing a simpler, more regular bitstream. The format is most commonly encountered as a compression method within TIFF files (TIFF compression tag 4), where it became the standard archival format for scanned documents in enterprise document management, government records, and legal imaging systems. G4 compression is specified at 200, 300, or 400 dpi depending on the scanning application, with 300 dpi being the most common for archival-quality document imaging. One advantage is exceptional compression efficiency for document content: G4's two-dimensional prediction exploits the strong vertical correlation in text and line art pages, typically compressing a 300 dpi letter-size page to 30-50 KB — roughly half the size of equivalent Group 3 encoding. The format's entrenchment in document management infrastructure is another strength — G4 TIFF is the mandated format for many government digital records systems, court filing systems, and corporate archives, supported by every enterprise imaging platform.
Developer: ITU-T (CCITT)
Initial release: 1984

Frequently Asked Questions

What is the reason to convert PICON to G4?

PICON originated in Unix file managers and has narrow compatibility today. G4 offers high-speed fax compression encoding — a far more practical choice for sharing.

What apps support G4?

You can view G4 with ImageMagick, IrfanView, fax software, GIMP. These tools cover all major desktop and mobile platforms.

Can I convert multiple PICON files to G4 at once?

Convertio supports batch mode — drag in multiple PICON files and they all convert to G4 together, which is much faster than one-by-one.

Is PICON to G4 conversion free?

You can convert PICON to G4 for free on Convertio. Premium plans are available if you need higher throughput or larger file allowances.

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 — PICON to G4 conversion is fully supported.

How long does PICON to G4 conversion take?

Usually just seconds. PICON files are typically small, so the upload, conversion, and download process finishes very quickly on Convertio.