In an image communication apparatus for communicating a color image with a distant apparatus according to the ITU-T recommendations upon line connection, an original image is read by a scanner unit, and the size of the read original image is identified. If the identified size of the original image is smaller than the page size defined by the ITU-U recommendation, image data is generated by reading the original image upon adding invalid data to the original image to make it have a main scanning length equal to the main scanning length of the minimum page size defined by the ITU-T recommendation in reading the original image through the scanner unit, and the image data is compressed by a JPEG compressing unit and transmitted. In this case, the valid image area of the compressed data is set in accordance with the size of the original image. This allows the receiving side to read only the valid image area, decode the valid image area, and reproduce the image.