WebP to PAM Converter
Convert WebP to PAM in your browser. WebP files usually come from websites, Chrome's Save image as, CDNs and Android apps; PAM is the better fit for image processing pipelines that need alpha. You get an 8-bit PAM, RGB, or RGB_ALPHA when the image has 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
WebP expected · other image formats also work
How to use WebP to PAM
- 1
Add your WebP files: drop them here, choose them, or paste from the clipboard.
- 2
There is nothing to tune: the PAM is written uncompressed. Resizing and rotating are under More options if you need them.
- 3
Click Convert. Each file is decoded and encoded in a background thread on this device.
- 4
Download the .pam files one at a time or together as a ZIP.
Why use Aback Images for webp to pam
Where the PAM goes next
PAM opens in Netpbm, ImageMagick, FFmpeg and Photoshop.
PAM next to WebP
The PAM is written uncompressed, so expect it to be several times larger than the WebP, which stores lossy VP8 coding or lossless VP8L.
No new artefacts
WebP is already lossy, since it stores lossy VP8 coding or lossless VP8L; the PAM keeps the decoded pixels uncompressed, so this step adds no compression damage of its own.
Processed on your device
Your images are decoded, edited and encoded inside this browser tab by Web Workers. Nothing is uploaded to a server.
WebP vs PAM
What changes from WebP to PAM
Encoding: the WebP uses lossy VP8 coding or lossless VP8L; PAM uses none, and the download is an 8-bit PAM, RGB, or RGB_ALPHA when the image has transparency.
Bit depth: 8 bits per channel in the WebP; PAM allows 8 or 16 bits per channel, and the PAM written here has 8 bits per channel.
Colour: RGB; lossy WebP stores colour at half resolution (4:2:0) in the WebP; PAM supports greyscale or RGB, as declared by the TUPLTYPE line, written here as 8-bit sRGB.
Transparency: the WebP stores it as a separate alpha plane, available in lossy as well as lossless files; the PAM keeps it as an extra channel declared as GRAYSCALE_ALPHA or RGB_ALPHA.
Animation: ANMF frame chunks, each with its own delay and blending; the PAM holds one image, so only the first frame is converted.
Metadata: the WebP can carry EXIF, XMP and ICC chunks; PAM can carry only comment lines in the header, but nothing is copied across.
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.
WebP files usually come from websites, Chrome's Save image as, CDNs and Android apps.
About PAM
PAM is the general member of the Netpbm family: an uncompressed format with a self-describing header that can hold greyscale, RGB and alpha channels at 8 or 16 bits.
A PAM file starts with 'P7', then header lines WIDTH, HEIGHT, DEPTH (channels), MAXVAL and TUPLTYPE (for example RGB_ALPHA), closed by ENDHDR, followed by the raw samples row by row.
When converting WebP to PAM makes sense
PAM is the better choice for image processing pipelines that need alpha, while WebP suits images on websites and in apps.
PAM strengths: Alpha channel, unlike PPM; Trivial to parse; 8 or 16 bits per channel. Drawbacks to weigh: Uncompressed and large; Few apps outside Netpbm and ImageMagick know it.
Limitations
- WebP images saved from websites are often already resized and compressed for the page, so the result cannot be sharper than that copy.
- PAM keeps an alpha channel, unlike PPM, so tools that only know binary PPM cannot read it.
- Files are uncompressed at 4 bytes per pixel with alpha.
More conversions
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Frequently asked questions
Does converting WebP to PAM lose quality?
PAM is written uncompressed, so the pixels are stored exactly as decoded. Artefacts already in the WebP stay, but nothing new is lost.
Is transparency kept in the PAM?
Yes. WebP stores it as a separate alpha plane, available in lossy as well as lossless files, and the PAM is written with an alpha channel, so transparent areas stay transparent.
Will my animated WebP stay animated?
No. PAM holds a single image, so only the first frame is kept. Convert to animated WebP, APNG or GIF to keep the motion, or export every frame with the GIF Frame Extractor.
Which apps open PAM files?
Netpbm, ImageMagick, FFmpeg and Photoshop. It does not open in web browsers.
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.