Resolution or size changing of scanned objects can be accomplished on contour coded data using the information obtained in the boundary following of exterior and interior borders of objects. The compressed boundary following data has its resolution changed by scale factor multiplying after decoding. The rescaled image is placed into a memory store for display. Uncompressed data is resolution changed by boundary following the stored image to obtain the object boundary coordinates. These coordinates are concurrently multiplied by a scale factor, compared to the scaled coordinate of the previous boundary picutre element and either contour encoded to compress the shrunken image or directed to a second memory store for display. The coordinates of each successive point are changed by the multipliers that scale the coordinates by the consolidation ratios. Each coordinate is affected separately. Any rational reduction factor can be achieved.