PNG to Bytes Converter

Reads an uploaded PNG file's raw bytes, verifies its 8-byte PNG file signature, and outputs every byte as a plain comma-separated decimal number list — handy for pasting into source code, documentation, or a byte-level comparison. A free online tool from Staaarter, right in your browser.

Runs locallyUpdated 2026-07-26

Overview

Introduction

This tool reads a PNG file's raw bytes and lists every one as a plain decimal number, entirely in your browser.

It's a simple, readable alternative to a hex editor or Base64 encoding when you need to inspect or copy a file's exact byte values.

What Is PNG to Bytes Converter?

A client-side PNG-to-byte-list converter that reads an uploaded file's raw bytes, confirms it starts with a valid PNG signature, and joins every byte's decimal value with a comma and space.

Unlike the pixel-level converters in this category, this tool works on the file's literal bytes — headers, compressed chunk data, everything — not decoded pixel colors.

How PNG to Bytes Converter Works

The uploaded file's bytes are read directly (no canvas decoding involved) and checked against PNG's fixed 8-byte file signature before anything else happens.

Once validated, every byte in the file is converted to its decimal string representation and joined into one comma-separated line of text.

When To Use PNG to Bytes Converter

Use it when you need to inspect, document, or paste a small PNG's exact byte contents somewhere that expects plain numbers rather than Base64 or hex.

It's also useful for quickly generating a byte-array literal for embedding a small PNG directly in source code.

Features

Advantages

  • Runs entirely client-side; your file never leaves the browser.
  • Produces plain, human-readable decimal numbers rather than a compact but opaque encoding.
  • Validates the PNG signature up front, catching accidentally-uploaded non-PNG files immediately.

Limitations

  • Output size grows roughly 3-4x the original file size as text, so this isn't practical for large PNGs.
  • Unlike Base64, this format isn't compact enough for embedding in URLs or transport-oriented contexts.

Examples

Convert a minimal PNG signature

Input

An 8-byte file containing exactly the PNG signature

Output

"137, 80, 78, 71, 13, 10, 26, 10"

Each of the 8 signature bytes is listed in decimal, comma-separated.

Reject a non-PNG file

Input

A 4-byte file that isn't a PNG

Output

An error: "This file doesn't start with a valid PNG signature."

The signature check runs before any byte listing happens.

Best Practices & Notes

Best Practices

  • Use this on small files (icons, tiny sprites) where a readable byte list is practical; for larger files, Base64 is more compact.
  • Pair with the matching Bytes to PNG converter to verify a round trip reproduces the exact same file.

Developer Notes

The pure conversion logic mirrors the existing PNG to Base64 converter's structure — the same PNG signature check, but joining decimal byte values with Array.from(bytes).join(', ') instead of base64-encoding them.

PNG to Bytes Converter Use Cases

  • Embedding a tiny PNG's exact bytes directly in source code
  • Documenting or diffing a small PNG file's byte contents
  • Teaching or debugging PNG file structure at the byte level

Common Mistakes

  • Using this on a large PNG and getting an unwieldy amount of text — Base64 or direct binary handling is more practical at scale.
  • Forgetting that this reads the file's raw bytes, not decoded pixel colors — it won't match a pixel-level RGB/RGBA byte dump.

Tips

  • Combine with the Bytes to PNG converter to test round-tripping a file exactly.
  • If you need a more compact text representation, use the PNG to Base64 converter instead.

References

Frequently Asked Questions