What is a SPU file?
Created by Atari, the SPU file extension was used by Spectrum 512. It belongs to the binary format raster group of images. The Spectrum 512 supports a maximum of 512 colours and is a graphics application that operated on the Atari ST systems. It is no longer in use and considered obsolete presently.
How to Open SPU Files
How to Make SPU Files
Exact steps for creating SPU files will vary by program and operating system. Download one of the above listed programs and you should be able to follow typical procedure for opening files or creating files from the File menu. Typically you will select File > Open or File > New and continue through the prompts. Some programs may follow a different procedure for either creation or opening of files.