# pnggroup/libpng

LIBPNG: Portable Network Graphics support, official libpng repository

Repository: https://github.com/pnggroup/libpng
Canonical: https://ross.abutalabs.com/products/libpng
Homepage: http://libpng.sf.net
Language: C
License: NOASSERTION
License Family: other
Last push: 2026-06-26T15:37:31+00:00

## Health v2 (maintenance only)
Score: 72/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 89, release rhythm 35, longevity 100
- inputs: {"age_days": 5280, "days_push": 68, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1647, forks 810 (observed 2026-08-28T04:05:16.492125+00:00)

## What it is
libpng is the official reference C library for reading, creating, and manipulating PNG (Portable Network Graphics) raster image files. It has been in extensive use and testing since 1995 and depends on zlib for compression.

## Use cases
- decode png images in a c program
- write png files from application code
- manipulate png metadata and pixel data
- embed png support in a cross-platform app
- convert images to png format

## When to choose
- you need battle-tested, standard-compliant PNG support in C/C++
- you want the canonical reference implementation of the PNG spec
- you need a lightweight, dependency-light image codec

## When to avoid
- you need higher-level image processing beyond PNG encode/decode
- you are working in a language with its own native PNG support
- you need modern image formats like WebP or AVIF

## Facets
- artifact type: library
- maturity: stable
- function: image-processing, compression, file-system
- domain: graphics, image-processing, files
- platform: cross-platform, c, cpp
- tags: png, reference-implementation, c-library, raster-graphics

## Member repositories
- pnggroup/libpng (main) score 72

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:16.492125+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T03:45:21.053262+00:00, confidence not recorded.
  - readme: https://github.com/pnggroup/libpng (fetched 2026-08-28T04:05:16.492125+00:00, sha 725f6293cc2d)
  - homepage: http://libpng.sf.net (fetched 2026-08-29T11:18:38.194598+00:00, sha 01b2da1261ba)
- Data as of 2026-08-30T08:39:29.467469+00:00.