1. An image data compression method for computer processor pipeline trace data, comprising: a block dividing step comprising dividing a computer processor pipeline statistic image to be displayed into a plurality of blocks with predetermined block width and block height; a block list creating step comprising creating a block list for indexed blocks containing meaningful pixels in said divided blocks such that said indexed blocks associated with each other, wherein said meaningful pixels are pixels corresponding to the computer processor pipeline raw trace data; and a pixel information compressing step comprising compressing original pixel information on the meaningful pixels in said indexed blocks and storing it in said block list.