Question 1

How did PCX become the first mainstream PC image format?

Accepted Answer

PCX was one of the first widely used image formats on IBM-compatible PCs, created by ZSoft Corporation for their PC Paintbrush program in 1985. Before Windows made BMP the default, PCX was the standard format for DOS-based graphics applications. It used simple run-length encoding for compression and supported up to 16 million colors in its later versions.

Question 2

How does PCX compression work?

Accepted Answer

PCX uses run-length encoding, a straightforward lossless compression scheme. When consecutive pixels share the same value, the encoder stores a count byte (with the two high bits set) followed by the pixel value, instead of repeating the value multiple times. Single unique bytes below 0xC0 are stored as-is. This keeps the format simple to parse while still reducing file size for images with solid-color regions.

Question 3

What color modes does this converter support?

Accepted Answer

This tool decodes all standard PCX color modes: 24-bit RGB (3 planes at 8 bits each) for full-color photographs, 256-color indexed images that use a VGA palette stored at the end of the file, and 1-bit monochrome for line art and scanned documents. The built-in RLE decompressor handles both compressed and uncompressed variants.

Convert PCX

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