This means that they can be compiled directly into an application without any preprocessing steps, but it also makes them far larger than their raw pixel data.

XBM image data consists of a line of pixel values stored in a static array.

If the image width does not match a multiple of 8, the extra bits in the last byte of each row are ignored.

[6] XBM support was removed from Internet Explorer 6, Mozilla Firefox 3.6,[7] and WebKit-based browsers.

[13] Despite having been superseded by the XPM format, XBM is still used by some modern but lightweight window managers like Openbox to define simple button images in a window's title bar, such as the iconify/minimize, restore, and maximize buttons.