WebP Won't Open? Rename Does Nothing, Convert Instead
Short answer: if a picture opens in Chrome but Word, older Photoshop, a Windows app, or an upload form rejects it, you are almost certainly holding a WebP, and renaming the file to .jpg will not help. We encoded one image three ways and read the first bytes of each: the WebP began with the ASCII letters RIFF, the JPEG began with the hex bytes FF D8 FF, and the PNG began with 89 50 4E 47. Those opening bytes, called magic bytes, are what strict apps check. A renamed WebP keeps its RIFF bytes, so the app still says no. The one thing that works is a real conversion that decodes the pixels and re-encodes them as JPEG or PNG, which produces a file that genuinely starts with the right signature. The Image Converter does that in your browser without uploading anything, and our WebP versus JPEG guide covers the format side in depth.
Why does it open in Chrome but not in Word or Photoshop?
Because the two use different strategies to decide what a file is. A browser content-sniffs: it reads the actual bytes, recognizes a WebP stream, and renders it, regardless of what the file is called. Word, older versions of Photoshop, many Windows viewers, and most upload forms take the strict path instead. They read the magic bytes at the very start of the file and compare them against the signatures they expect. A WebP opens with the letters RIFF and, a few bytes later, WEBP. That is not the JPEG signature, so a strict decoder rejects the file or reports it as corrupt.
Neither side is wrong. The browser is being helpful and the strict app is being careful. But it means the same file can look perfectly fine in one place and broken in another, which is exactly the confusion this guide clears up.
Does renaming a .webp file to .jpg make it a JPEG?
No. We tested this directly. We drew a single 300x200 image on a canvas and encoded it three times, once as WebP, once as JPEG, and once as PNG, then read the first sixteen bytes of each result. They were completely different:
- WebP opened with the ASCII letters RIFF, followed by a size, then WEBP, then the codec marker VP8X. Those four letters at the start are the format's signature.
- JPEG opened with the hex bytes FF D8 FF E0, followed by the JFIF identifier. This signature is what a JPEG decoder looks for.
- PNG opened with the hex bytes 89 50 4E 47 and the text IHDR, its own unmistakable header.
Renaming a file edits only the file-system entry, the name. It does not touch a single byte of the content. The file still begins with RIFF, so any app that checks the header sees a WebP wearing a .jpg costume. This is why the popular trick of renaming the extension fails so often, and why the fix has to change the bytes, not the label.
What actually opens a WebP in a stubborn app?
A true re-encode. You decode the WebP back to raw pixels, then encode those pixels as a JPEG or PNG. That produces a brand new file whose first bytes really are the JPEG or PNG signature. Now the strict decoder reads a header it recognizes and opens the file without complaint.
The quickest routes, depending on what you have:
- A browser, if you can open it there. Since browsers render WebP fine, open the file in Chrome or Edge, then use Save As and pick JPEG or PNG as the format. This re-encodes rather than renames, so the output is a genuine JPEG.
- A converter tool. Our Image Converter reads the WebP in your browser, decodes it, and writes a real JPEG or PNG. Nothing is uploaded, and the output starts with the correct magic bytes because it is truly a new encoding.
- An image editor. Opening the WebP in any editor that supports it and exporting as JPEG or PNG also re-encodes the pixels, which is the same principle.
The common thread is that all three decode and re-encode. None of them rely on the file name.
Why is a renamed WebP file still huge or still broken?
Because renaming never altered the content. A renamed WebP keeps its exact bytes, so it keeps its size and its WebP encoding. If your goal was a smaller file, renaming did nothing. If your goal was compatibility, renaming did nothing there either. The only step that moves either number is a re-encode, which replaces the WebP payload with a fresh JPEG or PNG payload and a fresh header.
Is WebP actually smaller than JPEG?
Usually, and our test showed it. Encoding the same 300x200 image at the same quality produced a WebP payload of 4,144 base64 characters, a JPEG of 5,800, and a PNG of 8,864. The WebP came out about 29 percent smaller than the JPEG for identical dimensions. That compression advantage is the whole reason websites serve WebP, and it is also why you should keep the WebP whenever the receiving app accepts it. Convert a copy only for the stubborn apps that check the header.
What are the honest limits?
- We tested in a browser, not in Word or Photoshop. We confirmed the magic-byte signatures and that a browser content-sniffs a mislabeled WebP and still renders it at the correct 300x200 size. We did not have Word or Adobe installed to reproduce their exact rejection message. Their header checking is documented behavior, but the precise error wording will differ by version.
- One browser only. The content-sniffing result came from headless Chrome. Other modern browsers also sniff, but we tested one engine, so treat the browser side as strong evidence rather than a guarantee across every browser.
- Browser-generated WebP. Our WebP carried the VP8X marker, the extended variant that supports animation and transparency. Real WebP files from the web may use VP8 for lossy or VP8L for lossless instead, but all of them sit inside the same RIFF and WEBP wrapper, so the rename-still-fails finding holds for every variant.
- Conversion is a fresh encode. Decoding recovers the exact pixels, so nothing is lost reading the WebP. The new encode is where change happens: PNG stays lossless but is larger, while JPEG re-compresses and can add mild artifacts, especially if the file is converted more than once.
- Animated WebP is a separate case. A multi-frame WebP converted to a single JPEG or PNG keeps only the first frame. If animation matters, convert to GIF or keep the WebP rather than flattening it.
What did we actually test?
We ran a page in headless Chrome on Windows (2026-10-26) that drew one 300x200 canvas image and encoded it through the browser's own encoder as image/webp at quality 0.9, image/jpeg at quality 0.9, and image/png. We decoded each result from base64 and read the first sixteen raw bytes. The WebP began 52 49 46 46 (RIFF) with WEBP and VP8X later in the header. The JPEG began FF D8 FF E0 followed by JFIF. The PNG began 89 50 4E 47 followed by IHDR. Payload sizes were 4,144, 5,800, and 8,864 base64 characters respectively. We then wrapped the WebP bytes in a blob labeled image/jpeg and loaded it into an Image element, which rendered successfully at 300x200, confirming that the browser sniffs content rather than trusting the label.
What this test does not cover: it used one browser engine and browser-generated images rather than files downloaded from real websites, and we did not open the renamed file in Word, Photoshop, or a specific upload form to capture their rejection. The magic-byte signatures and the size ordering are stable properties of the formats and hold broadly, but a specific app may report a different error, and an animated WebP will not survive conversion to a still image.
Quick FAQ
Why does my WebP open in Chrome but not in Word or Photoshop?
Browsers content-sniff: they look at the actual bytes and render whatever they recognize, so a WebP displays even inside a file named .jpg. Word, older Photoshop versions, and many upload forms instead check the magic bytes at the start of the file. A WebP begins with RIFF and WEBP markers, not the JPEG signature, so those apps refuse it. The file is fine; the app is strict.
Does renaming a .webp file to .jpg make it a JPEG?
No, and this is the trap most people fall into. We encoded the same image as WebP, JPEG, and PNG and read the first bytes of each: WebP began with the ASCII letters RIFF, JPEG began with the hex bytes FF D8 FF, and PNG began with 89 50 4E 47. Changing the file name touches only the name. The bytes inside stay WebP, so any app that checks the header still sees a WebP.
How do I actually convert a WebP to JPG?
You have to decode the WebP pixels and re-encode them as JPEG, which produces a genuinely new file starting with the JPEG signature. Our Image to PDF and Image Converter tools do this in your browser: the output is a real JPEG, not a renamed one. Opening the WebP in a browser and using Save As normally re-encodes it too, provided you pick JPEG or PNG as the format.
Why is a renamed WebP file still huge or still broken?
Because the content never changed. A renamed WebP keeps its original bytes, so it keeps its size and its WebP encoding. If the goal was a smaller file, renaming achieved nothing. If the goal was compatibility, renaming achieved nothing either. Only a re-encode changes both the header and the data.
Is WebP smaller than JPEG for the same image?
In our test it was. We drew one 300x200 image and encoded it three ways at the same quality: the WebP payload came to 4,144 base64 characters while the JPEG came to 5,800 and the PNG to 8,864, making WebP about 29 percent smaller than the JPEG. That compression advantage is why sites serve WebP, and it is also why you may want to keep the WebP and only convert a copy when a strict app needs one.
Will converting WebP to PNG or JPEG lose quality?
Decoding the WebP recovers its exact pixels, so nothing is lost in reading it. The change happens at the new encoding step. Converting to PNG stays lossless but is often larger, since PNG is less efficient for photos. Converting to JPEG re-compresses the pixels and can add a small amount of artifacts, especially if you convert a second time. For a photo destined for a strict app, JPEG is usually the right trade.
Once the file opens in the stubborn app, if you also need it smaller for email or a portal, the Image Compressor brings the converted copy down without a second trip through a converter.