Sun Raster (.sr)
The Sun Raster (SR) file extension, is a raster graphics file format developed by Sun Microsystems for use on their SunOS operating system. This format, which stores black-and-white, grayscale, and color bitmapped data, was widely used in UNIX-based systems and supported by various imaging applications. The Sun Raster format includes a header, an optional color map, and the bitmapped image data. Although it does not support transparency, it remains a simple and widely distributed bitmap format.