How to remove AI metadata from a PNG

An AI-generated PNG can hide data in several places: text chunks that hold the prompt, an XMP packet, an EXIF chunk and a C2PA manifest chunk. List them all with `exiftool -a -G1 file.png`, delete them, then list again. Saving the pixels to a fresh file removes every chunk at once.

Last updated: 2026-10-08

Why a PNG is a special case

A JPEG stores metadata in a handful of well-known segments. A PNG is built from chunks, each with a four-byte type, and the format lets anyone add a chunk. That flexibility is why generation tools use it: they can write whatever they need, and decoders skip chunks they do not know.

If you want the three text chunk types explained, read how to strip text chunks from a PNG. This page covers the other half of the question: all the places an AI image can keep something, and how to be sure you found them.

A map of where things hide

• tEXt, zTXt, iTXt text chunks: Automatic1111 writes a parameters entry with the prompt, negative prompt, sampler, steps and seed. ComfyUI writes prompt and workflow entries that hold a JSON description of the node graph.
• iTXt with an XMP keyword: an XMP packet can be stored as an international text chunk, and it can name the tool, the creation tool and a source type.
• eXIf: an EXIF block. Some tools write one in a PNG, and it can hold dates, software tags or a comment.
• caBX: the chunk used by C2PA to carry a manifest in a PNG, as JUMBF data. ExifTool lists it under C2PA, and says the JUMBF group can be deleted from writable PNG files.

A tool that reports only text chunks will miss the last three. That is the usual way a cleaned file still gets labelled.

Removing everything

ExifTool does the job in one pass. The command exiftool -all= file.png deletes writable metadata, and the C2PA group may need -jumbf:all= if it is still listed. ExifTool leaves the old file with an _original suffix by default. Keep it until you have checked the result, and delete it afterwards if you do not need it. Its manual warns that the overwrite option should be used only with separate backups.

An alternative is to build a new file from the pixels. Decode the image to an array, create a new image from that array and save it without copying the info dictionary. Because the new file never had the chunks, nothing has to be found and deleted. That is the approach PassReal uses, and its report counts what the original carried: on a Gemini export, 174 markers before and 0 after.

Verification you should not skip

The failure mode is quiet. A tool says done, and a chunk is still there.

• List the groups on the output with exiftool -a -G1 -s.
• Look for a caBX chunk or a JUMBF entry specifically.
• Open the file in a second viewer. Different tools read different things.
• Upload the cleaned file to the place that was labelling it, if you can test it safely, and see whether the label is gone.

What this does not fix

Removing metadata changes what a file says. It does not change what the picture contains. If the generator embedded a watermark in the pixels, as SynthID does for Google tools, it stays. If a detector reads pixel statistics, it reads the same pixels. In our tests, ZeroGPT still gave scores of 0.96 to 0.97 on images that PassReal had processed, which is why this site does not promise detector results.

An empty file is also its own tell. Cameras write EXIF, so a PNG or JPEG with no metadata at all is unusual. If that matters for your use, see how to add EXIF data to an AI image.

Choosing a method

For one or two files, ExifTool is exact and free. For many, a folder-wide command or a batch service saves time. In both cases, verify the output once by hand before you trust the process.

Questions

Process three images free

Three images, no card, no expiry.