PBM to CBZ Converter
FileFlip converts PBM to CBZ entirely inside your browser, using ImageMagick and MuPDF compiled to WebAssembly. The file is never uploaded to a server: it is read off your disk, converted on your own machine, and saved back by the browser. That means no file-size limit, no queue and no account.
How do I convert a PBM file to CBZ?#
- Drop your PBM file onto the converter at the top of this page, or click it to pick one from your computer. You can add as many as you like.
- Leave the target set to CBZ and the conversion starts on its own. FileFlip downloads 24.1 MB of WebAssembly the first time and nothing after that, then runs ImageMagick and MuPDF on your own machine.
- Save the CBZ file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting PBM to CBZ lose quality?#
No. The PBM picture is placed into the CBZ document at its full resolution, so every pixel reaches it intact. What you give up is that it becomes a picture inside a document rather than text.
Is it safe to convert PBM files online?#
Yes, because nothing is uploaded. FileFlip converts PBM files inside the browser tab you already have open, using WebAssembly builds of the same engines a desktop converter would install. Your file is read from your own disk into the page's memory, and no request carrying it is ever made.
You do not have to take that on trust. Open your browser's network panel, run a conversion, and you will see the engine come down and your file go nowhere. There is no upload, no server-side copy, no retention window, and no account tied to what you converted.
How FileFlip works lists every engine, its version and its download size, and shows how to check for yourself that nothing leaves your machine.
What PBM to CBZ actually does to the file#
Converting PBM to CBZ runs on ImageMagick and MuPDF, downloads 24.1 MB of WebAssembly the first time and nothing after that, places the picture into the document at full resolution.
| Engine | ImageMagick and MuPDF |
|---|---|
| Conversion path | 2 steps: PBM → PNG → CBZ |
| Downloaded to your browser | 24.1 MB, once, then cached by your browser |
| Quality | Pixels preserved |
| You get back | One file |
| Where it runs | In a background worker, so the page stays responsive |
Worth knowing before you start:
- the picture is placed in the document as a picture; no text is recognised out of it
What is a PBM file?#
A PBM file stores a strictly black-and-white, one-bit-per-pixel raster image as plain ASCII characters or packed binary bits, in the Netpbm project's Portable Bitmap format.
Use PBM for a strictly black-and-white bitmap, such as a fax page or a stencil mask, that needs to move between tools without any image library.
Convert PBM to PNG once the image needs compression or has to sit alongside greyscale or colour images in the same pipeline.
What is a CBZ file?#
A CBZ file is a ZIP archive of page images, usually JPEG or PNG, named so they sort into reading order, with nothing else defining it as a comic beyond that convention.
Use CBZ to distribute a scanned or digital comic as sequential page images that any comic reader opens without conversion.
Convert CBZ to PDF when a comic needs to move into software that expects a page-based document instead of a folder of images.
PBM to CBZ questions people ask#
What does PBM stand for?
PBM stands for Portable Bitmap, the black-and-white member of the Netpbm family of image formats that Jef Poskanzer created to move images between Unix tools. It is the strictly one-bit sibling of the colour PPM and greyscale PGM formats.
Is a 1 a black pixel or a white pixel in a PBM file?
In a PBM file, a 1 represents a black pixel and a 0 represents a white pixel, which is the opposite of what many people expect from a plain greyscale scale. This is defined directly in the Netpbm project's own PBM specification.
Why is my PBM file bigger than a similar PNG?
A PBM file stores one bit per pixel with no compression at all, while PNG compresses that same data losslessly, so a large black-and-white image can end up many times smaller as a PNG. PBM trades file size for a format simple enough to read and write without any image library.
What is a CBZ file?
A CBZ file is a ZIP archive holding a comic's pages as individual image files, named so they sort into the right reading order. There is no page-layout data or text encoding involved, which is the entire format: a comic reader just opens the ZIP and displays the images in sequence.