An image compression method, comprising: identifying representative values of pixel values making up a block having a predetermined size in an image; representing each of the pixel values by one of the representative values; identifying a pattern of the pixel values, as represented by the representative values, the pattern comprising bits as pattern values of the same number as the number of the pixel values; compressing the pixel values using the representative values and the pattern; and transmitting a part of the bits to an image restoring apparatus; wherein the identifying of the pattern further comprises: arranging the pixel values as represented by the representative values in a predetermined order to generate arranged representative values representing the arranged pixel values; and generating the pattern by setting a first value of the arranged representative values to a predetermined first pattern value which is independent of the first value, setting any other representative values of the arranged representative values with the same value as the first value to the predetermined first pattern value, and setting all remaining representative values of the arranged representative values to a second pattern value, and wherein the part of the bits is characterized by omission of the first bit of the pattern. identifying representative values of pixel values making up a block having a predetermined size in an image; representing each of the pixel values by one of the representative values; identifying a pattern of the pixel values, as represented by the representative values, the pattern comprising bits as pattern values of the same number as the number of the pixel values; compressing the pixel values using the representative values and the pattern; and transmitting a part of the bits to an image restoring apparatus; wherein the identifying of the pattern further comprises: arranging the pixel values as represented by the representative values in a predetermined order to generate arranged representative values representing the arranged pixel values; and generating the pattern by setting a first value of the arranged representative values to a predetermined first pattern value which is independent of the first value, setting any other representative values of the arranged representative values with the same value as the first value to the predetermined first pattern value, and setting all remaining representative values of the arranged representative values to a second pattern value, and wherein the part of the bits is characterized by omission of the first bit of the pattern. arranging the pixel values as represented by the representative values in a predetermined order to generate arranged representative values representing the arranged pixel values; and generating the pattern by setting a first value of the arranged representative values to a predetermined first pattern value which is independent of the first value, setting any other representative values of the arranged representative values with the same value as the first value to the predetermined first pattern value, and setting all remaining representative values of the arranged representative values to a second pattern value, and wherein the part of the bits is characterized by omission of the first bit of the pattern.