Why does Photoshop say "not the right kind of document" when I open a PNG?

This error means the file does not start with the PNG signature (89 50 4E 47 0D 0A 1A 0A) or has a structure that Photoshop does not recognize as PNG. It is often caused by a JPEG or WebP file saved with a .png extension.

Can I fix a PNG that gives a "file-format module" error without Photoshop?

Yes. Open the file in a browser and save a new copy. The browser writes a clean chunk structure. If the browser cannot open it, use a PNG rebuilding tool or an online repair service.

What is a CRC error in a PNG file?

A CRC (Cyclic Redundancy Check) error means the checksum inside a PNG chunk does not match the chunk's data. Strict readers like Photoshop reject the file. Browsers often ignore CRC errors and display the image anyway.

How can I tell if my file is really a PNG?

Open the file in a hex viewer and check the first eight bytes. They must be 89 50 4E 47 0D 0A 1A 0A. If you see different bytes, the file is not a PNG and needs to be renamed or converted.

Photoshop Can't Open a PNG: "File-Format Module" Errors

Photoshop refuses a PNG with one of two errors: "Could not complete your request because the file-format module cannot parse the file" or "Could not complete your request because it is not the right kind of document." Both mean the same thing. Something inside the file does not look like a valid PNG to Photoshop's parser. The fix rarely requires Photoshop itself. You can solve almost every case with free tools and a few minutes.

What the Photoshop PNG Errors Actually Mean

The first error, "the file-format module cannot parse the file," signals that the file's internal structure does not match what Photoshop expects from a PNG. The second, "it is not the right kind of document," is blunter: Photoshop does not think the file is a PNG at all.

Both point to one of these problems:

The file is not a PNG but carries a .png extension.
The PNG has a damaged chunk or a CRC error that Photoshop's strict parser rejects.
The file contains unusual metadata or program data that confuses the parser.

Figure out which case you have and you will know the fastest fix.

The Most Common Cause Wrong Extension

Spot a File in Disguise

The most frequent reason a PNG will not open is a file saved with a .png extension that is actually a different format. A WebP or a JPEG wearing a .png name is the usual culprit. This happens when you download an image from a site that serves one format under another's name, or when someone renames a file without converting it first.

Open the file in a plain text editor or a hex viewer. A real PNG always starts with the eight-byte signature 89 50 4E 47 0D 0A 1A 0A. If you see "JFIF" you have a JPEG. "WEBP" means it is a WebP. The file is mislabeled.

Rename it to the correct extension. Then open it in Chrome, Firefox, or Edge, right-click, and save a new copy as PNG. The save function writes a clean chunk structure and gives you a real PNG that Photoshop can open.

When the File is a PNG but Damaged

If the file starts with the correct PNG signature but still throws an error, the problem is a damaged chunk or a CRC mismatch. PNG files are built from chunks of data, each with its own checksum. Photoshop rejects any file where those checksums do not match. A browser may display the image anyway. It is more tolerant.

When you can open the image in a browser, even if it looks wrong, use the browser to save a new copy. The browser reinterprets the image data and writes a fresh, clean PNG. This discards the corrupt parts and rebuilds a valid chunk structure.

Rebuild the PNG with a Browser Save

Drag the corrupted PNG into Chrome, Firefox, or Edge.
If the image appears, right-click it and choose "Save image as...".
Give it a new filename and keep the .png extension.
Open the new file in Photoshop. The error should be gone.

If the browser cannot open the file either, you need a tool that rebuilds the PNG from its raw data.

Unusual Metadata or Program Data

Strip Problematic Metadata

Some PNGs carry extra chunks that Photoshop's parser does not expect. Metadata from a nonstandard source, a color profile in an unusual form, or program-specific annotations can trigger the parse error. The chunks may be valid by the PNG specification. Photoshop is simply stricter.

Strip the offending metadata while keeping the image data intact. Open the file in a browser and save a new copy. The browser discards chunks it does not understand and writes a minimal, valid PNG.

Use a PNG Rebuilding Tool

Several free utilities read a PNG, validate its structure, and write a corrected version. They parse each chunk, check its CRC, and discard anything that fails the check or is not recognized. The output is a clean PNG that Photoshop opens without complaint. This is the same process that online repair services use; you can run it locally if you prefer.

Preventive Checks Before You Try to Open

Run these quick checks before you spend time on repairs. Confirm the file is a PNG at all.

Check the file extension. If the name reads image.png.jpg or image.png.webp, strip the wrong extension. Windows and macOS may hide the real one.
View the file in a hex viewer. The first eight bytes must be 89 50 4E 47 0D 0A 1A 0A. Anything else means it is not a PNG.
Open the file in a browser. If the image shows, the file is at least partially valid. Save it as a clean PNG right there.

If none of these checks work, the file may be too damaged to repair without a dedicated tool.

What to Do When All Else Fails

You have tried renaming, saving through a browser, and stripping metadata. Photoshop still shows the same error. The PNG likely has structural damage a simple re-save cannot fix. Reach for a tool that rebuilds the PNG from the raw compressed image data. Services like png.repair scan the file for valid IDAT chunks and reconstruct a working PNG from whatever image data remains.

A PNG that no program can open may have lost its image data permanently. But most cases are only partially corrupt, and a recovery attempt succeeds. Try the simplest fixes first: check the extension, open in a browser, save a clean copy.