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A free scan shows the junk files, broken settings and background clutter dragging Windows down - then fixes them in one click.Free scan · Windows 10 & 11Photoshop usually shows “Not a PNG file” because the file’s contents do not match PNG data—not because the .png label is wrong in isolation. Make a copy, identify the file’s real format, and re-download or re-export it before changing Photoshop settings. Troubleshoot Photoshop itself only when several independently verified PNG files fail.
What the error means
A filename extension is only a label. A valid PNG datastream starts with the eight-byte signature 89 50 4E 47 0D 0A 1A 0A, followed by PNG chunks beginning with IHDR and ending with IEND, as defined by the PNG specification. Photoshop checks the internal bytes when you open, place, import, or process a file. If those bytes identify JPEG, WebP, GIF, HTML, an incomplete download, or damaged data, the PNG decoder rejects it.
The failure is usually one of four things:
- Wrong extension: an intact JPEG, WebP, GIF, or other file was given a
.pngname. - Incomplete or corrupted data: bytes were lost during downloading, copying, or storage.
- Non-image content: a zero-byte file, cloud placeholder, or web-server error page was saved with a PNG-looking name.
- Photoshop-side trouble: preferences, plug-ins, graphics drivers, or the installation are interfering—more likely when many known-good PNGs fail.
Fastest safe diagnostic
- Duplicate the file. Keep the original untouched and perform tests on the copy.
- Reveal the complete filename. In Windows File Explorer, choose View > Show > File name extensions. Look for names such as
image.png.jpg,image.png.webp,image.png.html, orimage.png.tmp. - Check its size. A zero-byte file cannot be repaired by renaming it. An unexpectedly small file suggests an interrupted transfer.
- Read the file signature. Use the commands below rather than editing the binary in a text editor.
- Act on the result. Rename only when the real format is confirmed; otherwise obtain a fresh copy or re-export it.
How to verify the actual file type
Windows PowerShell
Open PowerShell in the file’s folder and run:
Format-Hex -Path ".image.png" -Count 16A genuine PNG begins with:
89 50 4E 47 0D 0A 1A 0AOther common headers are JPEG FF D8 FF, GIF 47 49 46 38, WebP 52 49 46 46 followed later by 57 45 42 50, and PDF 25 50 44 46.
macOS or Linux
Use the file-identification command:
file image.pngFor a direct hexadecimal view, run:
xxd -l 16 image.pngThese commands identify or display the header; they do not repair the file. If the beginning contains readable text such as <!DOCTYPE, <html, or a server error message, you downloaded a web page rather than an image.
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If the file is really JPEG, WebP, GIF, or another format
Make a copy, change the copy to the matching extension, and open it:
image.png → image.webpThen use Photoshop’s Save As or Export command to create a new PNG if that is the required deliverable. Renaming changes the label; it does not convert the data. Do not rename every failed file to .jpg as a guess. JPEG cannot store alpha transparency, and conversion cannot restore transparency, animation, metadata, or image information that the source format never contained. Real-world reports of mislabeled JPEG and WebP files appear in the Adobe Community and this documented example.
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If it is a genuine PNG that Photoshop cannot open
Get an undamaged copy
- Download it again from the original source.
- Ask the sender for the original attachment or an unmodified export rather than a preview.
- Copy it to a local drive before testing; avoid network shares, removable media, and online-only cloud placeholders.
- If the file came from a browser, cloud service, messaging app, or authenticated site, confirm that the download completed instead of saving a preview or error response.
A thumbnail or browser preview is not proof that the file you possess is complete. Another decoder may be displaying a cached or partially repaired version.
Test another application
Try Windows Photos or Paint, macOS Preview, a browser, or another image editor. Use the result to choose the next step:
| Test result | Most likely explanation | Next action |
|---|---|---|
| No application opens it | Corruption, incomplete download, or non-image content | Retrieve the original again; do not keep changing extensions |
| Another application opens it, Photoshop does not | Photoshop compatibility or a file-structure issue | Re-export a new PNG, then test that new file |
| Only one file fails | File-specific problem | Inspect its source, size, and header |
| Several files from one source fail | Bad export or transfer pipeline | Request a fresh export or use a different download method |
| Every known-good PNG fails | Photoshop, plug-in, driver, or permissions issue | Follow the Photoshop troubleshooting section |
Re-export without destroying the original
If another program can decode the image, use its Save As or Export command, choose PNG, and save under a new name such as recovered-image.png. A Paint re-save is a commonly reported workaround, but it is a re-export, not proof that the original was valid; applications can flatten transparency, change color profiles, discard metadata, or alter animation. Before deleting the source, compare transparent areas, canvas dimensions, colors, image quality, and any animation or metadata you need.
When Photoshop itself is the problem
Adobe lists PNG as a supported Photoshop format in its format documentation. If newly created or independently sourced PNGs all fail, use this order:
- Restart Photoshop and the computer, then update Photoshop through Creative Cloud.
- Temporarily disable third-party plug-ins and test again.
- Test the graphics processor: on Windows choose Edit > Preferences > Performance; on macOS choose Photoshop > Settings > Performance. Clear Use Graphics Processor, restart Photoshop, and retry. Adobe describes this as a diagnostic step, not a confirmed universal fix for this message. See Adobe’s GPU guidance.
- Reset preferences: choose Edit > Preferences > General on Windows or Photoshop > Settings > General on macOS, select Reset Preferences On Quit, and close Photoshop. Alternatively, close Photoshop and launch it while holding Alt + Ctrl + Shift (Windows) or Option + Command + Shift (macOS). Back up custom settings first. Adobe documents these methods in its preference-reset guide, updated February 23, 2026.
- Check drive permissions and available storage, test another operating-system user account, and reinstall Photoshop only after file-level causes are excluded. Adobe’s broader troubleshooting steps are at basic troubleshooting and crash and freeze troubleshooting.
Disabling the GPU or resetting preferences cannot turn a JPEG, WebP, HTML page, zero-byte file, or structurally damaged PNG into valid PNG data.
Common fixes that backfire
- Renaming to JPG: useful only when the header already proves the data is JPEG.
- Opening the file in Notepad: unreliable and potentially encourages accidental edits; use
file, PowerShell, or a hex viewer. - Overwriting the original: removes your best recovery copy. Keep separate original and recovered files.
- Trusting a thumbnail: thumbnails can be cached or generated by a different, more tolerant decoder.
- Uploading confidential files to online repair services: avoid this for client, medical, legal, copyrighted, or unreleased assets.
Quick decision table
| Symptom | Likely cause | Best response |
|---|---|---|
| Header is not PNG | Mislabeled format | Use the matching extension, then convert if needed |
| Header is PNG but size or transfer is suspicious | Incomplete or corrupted file | Obtain a fresh copy |
| File contains HTML text | Server, login, or download error | Download the actual asset after authentication |
| Another editor opens it | Decoder compatibility or minor structural damage | Re-export and verify transparency |
| All independent PNGs fail | Photoshop-side issue | Update, test plug-ins/GPU, reset preferences, then repair installation |
When to stop troubleshooting
If the header is not PNG, the file is zero bytes or HTML, and no application can decode it, Photoshop settings are not the solution—request the original file or a new export. For valuable or irreplaceable images, preserve the original, record its size and source, and work only on copies. A free editor such as GIMP may help with ordinary re-export; browser-based Photopea can be convenient for non-confidential files, but uploading sensitive assets introduces privacy and performance trade-offs.
Frequently Asked Questions
Can I rename a PNG to JPG to fix the error?
Only if file inspection proves that the underlying bytes are JPEG. Renaming alone does not convert or repair a file.
Why does the image open in Paint or a browser but not Photoshop?
Those programs may tolerate or repair structures that Photoshop rejects. Re-export a new PNG and verify transparency and dimensions before replacing the original.
Will resaving always preserve transparency?
No. The recovery application and its settings may flatten alpha, change colors, discard metadata, or alter animation. Inspect the result before deleting the source.
Should I reset Photoshop preferences for one failed file?
No. Reset preferences when multiple known-good PNGs fail or Photoshop shows broader abnormal behavior. A single mislabeled or damaged file is a file-level problem.
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