PDB to JBG Converter

Transform PDB to JBG — quick online conversion tool

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Fast Processing

PDB to JBG conversion is fast. Small files process almost instantly, and even larger images are done within moments.

Browser-Based Tool

Everything happens in the browser. Open the page, upload PDB, get JBG — no desktop software or extensions involved.

Batch Conversion

Convert multiple PDB files to JBG at once. Upload a batch and each file is processed independently — efficient and time-saving.

How to convert PDB to JBG

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose jbg or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your jbg file right afterwards

About formats

PDB (Palm Database) is a generic database container format created by Palm, Inc. for the Palm OS platform, first appearing with the original PalmPilot in March 1996. In the ebook context, PDB files most commonly use the PalmDOC or Plucker encoding to store readable text with basic formatting. The format consists of a 78-byte header identifying the database name, creation date, and record count, followed by a record index table and the data records themselves. PalmDOC-encoded PDB files use a simple LZ77-based compression scheme to pack plain text efficiently, while Plucker extends this with HTML rendering, image support, and hyperlink navigation. PDB ebooks powered a thriving mobile reading ecosystem years before dedicated e-readers existed — millions of Palm OS users carried entire libraries on devices like the Palm V, Tungsten, and Treo handhelds. A primary advantage is extreme simplicity: the flat record structure and minimal overhead mean PDB files parse instantly even on severely constrained hardware with limited memory and processing power. The open, well-documented structure is another strength, having spawned numerous reader applications across Palm OS, Windows, and later mobile platforms. Though the Palm platform is long discontinued, PDB ebooks remain accessible through conversion tools and readers like Calibre, and the format holds historical significance as one of the earliest practical mobile ebook solutions.
Developer: Palm, Inc.
Initial release: March 1996
JBG is a file extension for images compressed using the JBIG (Joint Bi-level Image experts Group) standard, formally ITU-T Recommendation T.82, completed in 1993 as a successor to the Group 3 and Group 4 fax compression standards. JBIG compression is designed for bi-level (black and white) images but can also handle grayscale and limited-color images by encoding each bit plane separately. The algorithm uses a form of arithmetic coding guided by an adaptive context model: for each pixel, the encoder examines a template of surrounding already-coded pixels to build a probability estimate, then feeds this estimate to a QM-coder (a variant of the Q-coder arithmetic coder) that produces a highly efficient binary output. JBIG achieves 20-40% better compression than Group 4 on typical document images, with the improvement being even larger on halftoned photographs and images with gradual density transitions where Group 4's simple run-length approach is less effective. The standard supports progressive encoding, where a low-resolution version of the image is transmitted first and progressively refined — useful for fax-like applications where the receiver can begin displaying the image before the full-resolution data arrives. One advantage is superior compression of documents containing halftone images: newspapers, magazines, and marketing materials that mix text with photographic halftones compress dramatically better with JBIG than with Group 3/4. The standard's ITU-T backing ensures it is implemented in document imaging hardware and software worldwide. JBG files are supported by ImageMagick and various document imaging tools.
Initial release: 1993

Frequently Asked Questions

Why convert PDB to JBG?

PDB is an obsolete Palm format. Converting to JBG provides bi-level image compression and opens your content to modern viewers.

What programs open JBG files?

Use ImageMagick, jbig-kit tools, IrfanView to view JBG files. The format is well-supported across desktop and mobile platforms.

Does the converter work on mobile devices?

The converter runs in your browser, so it works on mobile devices, tablets, and computers without any app installation.

Will image dimensions change during conversion?

The original resolution is preserved. Your JBG output has the same width and height as the source PDB file.

Is the conversion process secure?

All files are handled securely. PDB uploads are purged after processing, and resulting JBG files expire within 24 hours.

What if my PDB file is corrupted?

The converter validates your file on upload. If the PDB data is unreadable or corrupt, you will get an error before processing begins.