BGB File

What are BGB files and how to open them

Are you having problems opening a BGB file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your BGB files.

What is a BGB file?

A .BGB file is a Microsoft Chat Background Graphic file.

Microsoft Chat Background Graphic files are graphical background scenes used by Microsoft Comic Chat, a chat program that turns online conversations into illustrated comic panels. These background graphics define the setting behind the text bubbles and avatars in the comic panels, so that each chat session appears with a stylized backdrop rather than a plain color or window.

Created by Microsoft as part of Comic Chat versions 2.5 (and related versions), these files are assets supplied with the program or shared by other users. Comic Chat reads these background files at runtime to display them during conversations. Users sometimes download custom background graphics from fan sites or community collections to personalize the backdrop scene.

Background graphics originally appeared both as uncompressed bitmaps (BMP) in older versions (like 2.1), and later in a compressed, auto-downloadable format in version 2.5. Version 2.5 background files in this format embed metadata including a URL so that users' clients can fetch missing background graphics automatically from the network when another chatter uses a background the local machine does not have.

These graphics scenes contain bitmap image data, color, and layout information that Comic Chat blends with avatar and speech bubble rendering. Extraction tools such as AVBuster have revealed that embedded within these legacy compressed background files are standard bitmap graphics (BMP) that can be extracted for separate viewing or editing.

Background Graphic files begin with a byte signature that identifies them to the program: the first bytes at offset zero are 6 bytes long, specifically 81 81 03 00 02 00 in hexadecimal.

How to open BGB files

Important: Different programs may use files with the BGB file extension for different purposes, so unless you are sure which format your BGB file is, you may need to try a few different programs.

We have not yet verified any programs for Windows that work with this specific file format. If you know one, please use the 'Suggest a program' link below. Thanks!

Last updated: August 24, 2026

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