A PNG that refuses to open in Windows Photos or Paint is a common frustration. You double-click and get a blunt refusal: "It looks like we don't support this file format" in Photos, or "Paint cannot read this file. This is not a valid bitmap file, or its format is not currently supported" in Paint. The culprit is one of three things. The file might actually be a JPEG or WebP wearing a .png extension. The app itself might be the problem. Or the PNG is genuinely damaged. Here is how to tell them apart and fix each one, starting with the main search phrase: png won't open windows.

Check If the Problem is the App or the File

Do not assume the file is broken. Test it in a different program first. A web browser, Chrome, Firefox, or Edge, opens most image files without fuss. Drag the PNG file into an open browser window. If the image displays correctly, the file is fine. The fault sits with Windows Photos or Paint.

If the browser also fails to show the image, the file itself is the problem. Move to the next sections to identify whether it is really a different format or is damaged beyond easy repair.

Identify the Real File Format

Many files that appear to be PNGs are actually JPEGs, WebPs, or other formats that someone renamed. Changing the extension does not change the actual format. A true PNG file has a specific signature: the first eight bytes are 89 50 4E 47 0D 0A 1A 0A, which spells out "PNG" in hexadecimal. A JPEG file starts with FF D8 FF. A WebP file begins with "RIFF" and contains the string "WEBP".

How to Check the File Signature

Inspect the file signature using a hex viewer or a text editor that shows raw data. Open the file and look at the first few bytes. See 89 50 4E 47 at the start? It is a real PNG. See FF D8 FF? The file is actually a JPEG. If the first four bytes are "RIFF" and the next bytes include "WEBP", it is a WebP image.

When the file is not a PNG, rename the extension to match the actual format, .jpg for a JPEG file, for instance. Then try opening it in Photos or Paint again. If the app still refuses, the real format might be unsupported, but at least you know the file is not a broken PNG.

Fix a Damaged PNG

If the file signature confirms it is a PNG but the image still will not open, the file is genuinely damaged. A damaged PNG can sometimes be repaired by rebuilding it into a fresh valid PNG. This process extracts any readable image data and creates a new file that opens in most viewers.

One option is a dedicated repair tool. For example, png.repair processes a broken PNG and produces a working copy. The tool works online and does not add watermarks. Upload your damaged file and download the repaired version.

If the damage is severe, the repaired file may lose some parts of the image, but the main content is recovered in most cases.

Memory Limits and Large PNGs

Very large PNGs can fail in some apps because of memory limits, not damage. Windows Photos and Paint struggle with images that have very high resolution or large dimensions. Got a file several thousand pixels wide or tall? Try opening it in a different viewer that handles large files better, such as a web browser. If the browser opens it, the PNG is fine and the memory limit of the app is the cause. No repair is needed.

Common Error Messages and Their Meanings

Two specific error messages appear frequently when a PNG fails to open in Windows apps. Understanding them narrows down the cause.

  • "It looks like we don't support this file format." This message from Windows Photos usually means the file is not a format that Photos can read. It occurs when the file is actually a JPEG, WebP, or another type mislabeled as PNG. Check the file signature as described above.
  • "Paint cannot read this file. This is not a valid bitmap file, or its format is not currently supported." Paint reports this when the file either is not a valid bitmap format or is damaged. Verify the file signature first. If the file is a true PNG, the error points to damage.

Step by Step Troubleshooting

Follow these steps in order to resolve the issue.

  1. Open the PNG in a web browser. If it displays, the file is fine and the problem is with Photos or Paint. Use the browser or another image viewer instead.
  2. If the browser fails, check the file signature with a hex viewer. Look for 89 50 4E 47 (PNG), FF D8 FF (JPEG), or "RIFF"+"WEBP" (WebP).
  3. If the file is not a PNG, rename the extension to match the actual format, .jpg or .webp, for example. Try opening it again.
  4. If the file is a true PNG but still will not open, the file is damaged. Use a repair tool such as png.repair to rebuild it into a fresh valid PNG.
  5. If the repaired file still fails, the damage may be too severe. Recover the original file from a backup.

Prevent Future PNG Problems

To avoid "png not opening windows" or similar errors, keep these points in mind. Always save files with the correct extension. When you download an image, check that the extension matches the actual format. Use a reliable image viewer for very large files. Back up important images regularly so that a damaged file does not mean permanent loss.