Abstract: Image or character data in the form of a rectangular array of binary 1s and 0s (bits) are divided into a plurality of segments, such as thirty-two by thirty-two bit segments or one bit by eight bit or byte segments. The image data is scanned for identifying all-zero segments (background) which are ignored and non-zero segments (foreground) which are transmitted or stored with offset and length (number of successive non-zero segments). The compacted image data is suitably indexed for facilitating image expansion using simple techniques. All compaction and decompaction machine operations are independent of bit-significant informational content of the segments. Presentation of the uncompacted data uses any printer or display type of device.