To provide an image processor which is not required to execute the reading of an original manuscript again even when requested file formats are different regarding the same original manuscript.

The image processor is provided with a scanner 102 for reading image data from the original manuscript, a storage 104 for storing the image data in a JBIG format, an image receiver 107 for receiving the designation of the image data stored in the storage 104, a file format receiver 108 for receiving the designation of the file format, a converter 109 for converting the image data into the designated file format, and an output part 110 for outputting the image data. By this, the image processor is not required to execute the reading of the original manuscript again even when the requested file formats are different regarding the same original manuscript.