- See Doodle for other formats with that name.
Doodle is a raster image format used on Atari ST computers. It is apparently the native format of a paint program named Dr. Doodle.
Files are exactly 32000 bytes in size, and are essentially just a dump of video memory.
Doodle is supposed to be a high resolution (640×400) bi-level format, but in practice some .doo files contain a medium resolution (640×200) or low resolution (320×200) image instead. It is not possible to determine the resolution just by looking at the file, and presumably only high resolution format is portable.