The version of Paint in Windows 3.0, the first version of Windows many people actually used, could only open-not save-MSP files.

MSP format, which was specific to Microsoft Paint’s early versions, and is so obscure that it was actually deprecated by Microsoft before most people had a chance to use it.

(There was also a third format, the quickly forgotten. PCX faded out of view as higher-resolution raster formats became more common, it nonetheless was one of the most dominant image formats on the IBM PC during the late 1980s. (As mentioned above, Microsoft literally white-labeled a version of PC Paintbrush to give us Microsoft Paint.) While. PCX format was associated with PC Paintbrush, a hugely popular program in the days before Windows, so much so that it became a de facto standard for image editing in the days before GIF and JPEG. Microsoft was so concerned about the company that made PCPaint, Mouse Systems, that the MS-DOS maker licensed software from its largest competitor to make a drawing app of its own. The format is notable in the history of drawing programs, despite its hackneyed nature, because the approach was used with PCPaint, the very first drawing app for the IBM PC that used a mouse and a graphical interface. Because of BSAVE’s widespread use, early digitizer tools such as the VersaWriter drawing board relied on BSAVE to store screen-drawn graphics that could be re-displayed later. This works in many versions of Microsoft BASIC, the closest thing that there was to a truly cross-platform application during the early years of the personal computer industry.

(To load the image, of course, you use BLOAD.) This isn’t really a distinct format so much as a way to save a raw image of what’s on the screen using the BSAVE command offered in various versions of Microsoft QuickBasic. This format has a more direct lineage with the IBM PC.

File formats for pictures