Overview
Introduction
This tool inspects a PNG file's internal chunk structure and lists every textual metadata field stored inside it, right in your browser.
It's useful for checking what a PNG might be quietly carrying beyond its pixels: an author name, a description, a software credit, or a comment.
What Is PNG Text Extractor?
A byte-level PNG chunk reader that walks the file from its 8-byte signature onward, identifying every tEXt, zTXt, and iTXt chunk and decoding their keyword/text pairs.
It is strictly a metadata reader: it never attempts to recognize text rendered into the image's pixels, which is a fundamentally different (and much heavier) problem that needs a trained OCR model.
How PNG Text Extractor Works
The uploaded file's bytes are read directly; after confirming the standard PNG signature, the tool walks each length-prefixed chunk in order, checking its 4-byte type code.
For tEXt and uncompressed iTXt chunks, the keyword and text are decoded and shown in full; for zTXt and compressed iTXt chunks, only the keyword is shown alongside a note that the text is compressed, since decompressing it needs a zlib inflate implementation this lib deliberately doesn't include.
When To Use PNG Text Extractor
Use it to check whether a PNG you received or downloaded carries hidden authorship, comment, or software metadata before you republish or share it.
It's also handy for verifying that a metadata-writing tool (like the PNG Metadata Changer) actually wrote the field you expect.
Often used alongside PNG Text Remover, PNG Metadata Eraser and PNG Metadata Changer.
Features
Advantages
- Runs entirely client-side; the uploaded file is never sent to a server.
- Reads all three standard PNG text chunk types, not just the simplest one.
- Clearly distinguishes compressed entries it can't decode from ones it can, rather than silently failing.
Limitations
- This is not OCR: it cannot read text that's part of the image's rendered pixels, only text stored in the file format's own metadata chunks.
- Compressed zTXt and compressed iTXt entries are reported by keyword only, since decompressing them needs a zlib inflate step this tool doesn't implement.
Examples
Best Practices & Notes
Best Practices
- Check a PNG's text metadata before republishing it if you're unsure of its origin — it might reveal more than the pixels do.
- Pair this with PNG Metadata Eraser if you want to both inspect and then strip what you find.
Developer Notes
The lib function is a pure byte-walking parser (no DOM, no zlib dependency): it reads the PNG chunk stream directly off a Uint8Array, decoding tEXt with a simple Latin-1 decode and uncompressed iTXt with TextDecoder/Buffer, while zTXt and compressed iTXt are intentionally left undecoded and reported by keyword only.
PNG Text Extractor Use Cases
- Auditing a PNG for hidden author/comment metadata before sharing it publicly
- Verifying that a metadata-writing workflow embedded the expected keyword and text
- Investigating an unfamiliar PNG file's provenance
Common Mistakes
- Expecting this tool to read text visible in a photo or screenshot — that requires OCR, which this tool does not perform.
- Assuming a compressed zTXt/iTXt entry with no visible text means the chunk is empty, when it's actually just not decoded here.
Tips
- If you need the full text of a compressed zTXt/iTXt entry, re-export the PNG with metadata written as uncompressed tEXt/iTXt first.
- Run this before and after using the PNG Metadata Changer to confirm your edit landed correctly.