Default BMP Image Viewer in Windows 3.11

In Microsoft Windows 3.11, the built-in application responsible for opening and viewing image files with the BMP extension was Paintbrush. This article explains the role of Paintbrush as the default graphics utility in Windows 3.11, its core capabilities, and how users interacted with bitmap images in the operating environment.

The Default Viewer: Paintbrush

Paintbrush (executable name PBRUSH.EXE) was a standard utility included with Windows 3.0, 3.1, and Windows for Workgroups 3.11. Located within the "Accessories" group inside Program Manager, it served as both a basic raster graphics editor and the system's primary image viewer.

Because Windows 3.11 lacked a dedicated, standalone photo-viewing application like modern operating systems have, Paintbrush handled all default image display tasks for supported formats.

File Associations and Supported Formats

In Windows 3.11, File Manager (WINFILE.EXE) managed file extensions through associations defined in the system's WIN.INI configuration file. By default:

• .BMP (Bitmap): Automatically associated with Paintbrush. Double-clicking any .bmp file in File Manager immediately launched Paintbrush to display the image.
• .PCX (PC Paintbrush format): Also natively supported and opened by Paintbrush.

Paintbrush supported monochrome, 16-color, 256-color, and 24-bit bitmap formats, though actual display quality depended heavily on the user's installed graphics card and display drivers.

Legacy and Evolution

Paintbrush was licensed from ZSoft Corporation, the creators of PC Paintbrush for MS-DOS. It replaced the original monochrome "Paint" program found in Windows 1.0 and 2.0. With the release of Windows 95, Microsoft fully replaced 16-bit Paintbrush with the 32-bit "Paint" (MSPAINT.EXE), ending the era of PBRUSH.EXE as the default BMP viewer.