PNG chunk inspector

What this tool does

The inspector walks the PNG byte stream after the signature. It reports IHDR dimensions, each chunk type, and whether the CRC matches. Text is decoded; compressed zTXt is inflated when DecompressionStream exists.

How to use it

1. Drop a PNG.
2. Scan the chunk table.
3. Open text chunk values only as text.

Privacy

This tool processes files and text locally in your browser. Your content is not uploaded or stored by this site.

ConvertPass does not include your input in analytics, URLs, or error reports. Encoding: PNG binary. Limit: 25 MB (25.00 MB).

Limitations

• Broken CRCs are reported; the file is not auto-repaired.
• Ancillary chunks with unknown types are listed, not interpreted.

Example

image.png

IHDR 13 bytes, IDAT …, tEXt workflow, IEND

Troubleshooting

Not a PNG signature

The file may be a JPEG renamed to .png. Use the image information viewer.

FAQ

What is a tEXt chunk?

A Latin-1 keyword plus a text payload. ComfyUI commonly uses keywords prompt and workflow.

Does a failed CRC mean the image will not display?

Viewers often still show the pixels. A failed CRC means you should not trust that chunk’s bytes.

Can I edit a chunk?

Not in the inspector. Use the AI metadata remover or PNG rebuild path to drop text chunks.

Are iTXt compressed payloads supported?

Uncompressed iTXt is decoded. Compressed iTXt is flagged rather than silently guessed in this version.