PGM to WebP Converter
Convert PGM to WebP in your browser. PGM files usually come from computer vision datasets, depth sensors and scientific cameras; WebP is the better fit for images on websites and in apps. You get a lossy WebP at the quality you choose (lossless under More options), keeping transparency. Nothing is uploaded.
- Processed locally
- No upload, no wait
- No sign-up
- No watermark
Drop images here
or choose files · paste with Ctrl/⌘ V
PGM expected · other image formats also work
How to use PGM to WebP
- 1
Add your PGM files: drop them here, choose them, or paste from the clipboard.
- 2
Set the quality. 80 to 85 is visually close to the original for most photos.
- 3
Click Convert. Each file is decoded and encoded in a background thread on this device.
- 4
Download the .webp files one at a time or together as a ZIP.
Why use Aback Images for pgm to webp
Where the WebP goes next
WebP opens in every current browser, Windows, macOS, Android, and recent Photoshop, GIMP and Affinity.
WebP next to PGM
A lossy WebP usually comes out far smaller than the PGM, which stores none.
The first lossy pass
The PGM holds 8 or 16 bits per sample with nothing discarded yet. This conversion is the first lossy encode these pixels see, and hard edges and flat colour show it first.
Processed on your device
Your images are decoded, edited and encoded inside this browser tab by Web Workers. Nothing is uploaded to a server.
PGM vs WebP
What changes from PGM to WebP
Encoding: the PGM uses none; WebP uses lossy VP8 coding or lossless VP8L, and the download is a lossy WebP at the quality you choose (lossless under More options), keeping transparency.
Bit depth: 8 or 16 bits per sample in the PGM; WebP allows 8 bits per channel, and the WebP written here has 8 bits per channel. 16-bit PGM files, common for depth maps, are reduced to 8 bits.
Colour: greyscale only in the PGM; WebP supports RGB; lossy WebP stores colour at half resolution (4:2:0), written here as 8-bit sRGB.
Metadata: the PGM can carry only comment lines in the header; WebP can carry EXIF, XMP and ICC chunks, but nothing is copied across.
About PGM
PGM is the greyscale member of the Netpbm family, common in computer vision and scientific imaging.
A binary PGM starts with 'P5', the width, height and maximum grey value, then one sample per pixel. The plain 'P2' variant stores the samples as text.
PGM files usually come from computer vision datasets, depth sensors and scientific cameras.
About WebP
WebP is Google's web image format. It supports lossy and lossless compression, transparency and animation, and is typically 25 to 35 percent smaller than JPEG at the same visual quality.
A WebP is a RIFF file: 'RIFF', a length, 'WEBP', then chunks. A simple lossy file is one VP8 chunk and a lossless one is VP8L; the extended VP8X header announces alpha, animation, ICC, EXIF or XMP chunks.
When converting PGM to WebP makes sense
WebP is the better choice for images on websites and in apps, while PGM suits greyscale image processing.
WebP strengths: 25-35% smaller than JPEG; Transparency and animation in one format; Supported by every modern browser. Drawbacks to weigh: Some older desktop apps and photo printers cannot open it; Max 16383 px per side.
Limitations
- A PGM is greyscale, so the converted file is grey too even in a colour format.
- Depth maps and disparity maps saved as 16-bit PGM hold distances, not brightness; the converted picture is a visualisation of them.
- Many datasets store medical or thermal images as PGM with a narrow range of values, which can look almost uniformly grey until the contrast is stretched with Adjust Colours.
- A few older desktop apps, print services and upload forms still reject WebP; keep a JPG or PNG copy for those.
- WebP images are limited to 16383 pixels on each side.
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Frequently asked questions
Does converting PGM to WebP lose quality?
WebP is lossy, so detail the eye barely notices is discarded to save space. 16-bit PGM files, common for depth maps, are reduced to 8 bits.
What quality should I choose for WebP?
80 to 85 is visually close to the original for most photos. Go lower for thumbnails, or switch on Lossless under More options for screenshots and graphics.
Which apps open WebP files?
Every current browser, Windows, macOS, Android, and recent Photoshop, GIMP and Affinity.
Are my images uploaded anywhere?
No. Processing happens inside your browser with WebAssembly and Web Workers. The site only downloads the app code and codecs; your files never leave your device. You can confirm this with the live upload counter on the tool, or in your browser's network panel.
Can I process many files at once?
Yes. Drop a whole selection or folder. Files are processed in parallel on several worker threads, each result can be downloaded on its own, and everything can be saved as one ZIP.
Is it free? Is there a file limit or watermark?
It is free with no account, no watermark and no daily limit. The only limit is your device's memory: very large images (over roughly 100 megapixels) may be refused to keep the tab from crashing.