1. An image processing apparatus which performs image processing for an original image obtained by reading an original, comprising: a reading unit, adapted to read an original; a first conversion unit, adapted to convert an original image read by said reading unit into vector data; a second conversion unit, adapted to convert the vector data into image data; a comparison unit, adapted to compare first image data of the original image with second image data generated by said second conversion unit; and a selection unit, adapted to select the first image data or vector data as an electronic file corresponding to the original image on the basis of a comparison result from said comparison unit.