An image processing apparatus for converting image data between a raster format and a block format including an image data processor for providing the image data including a luminance component and at least one chrominance component in the raster format, at least two FIFO memories for storing corresponding image data components, a multiplexer for multiplexing the image data components from the at least two FIFO memories, a line buffer memory for storing outputs of the multiplexer linearly, and an image compressor for receiving the image data components in block format in sequence from the unified line buffer memory and compressing the received image data components. The image processing apparatus may also include an address generator for generating a common read/write address for the line buffer memory.