To absorb the difference of gradation characteristics depending on the types of digital camera and printers, and to obtain optimum image data reflecting user's tastes.

The image processor comprises an image input unit 101 for inputting image data from a recording medium having stored images acquired by taking objects, a gradation converter 102 for converting gradation characteristics of the image data to desired gradation characteristics, a table former 103 for forming a look up table usable for the gradation conversion, a mode selector 104 for selecting the type of objects, the model, etc. of objects, digital cameras or printers, a camera gradation table memory 105 for storing gradation characteristics per type of digital cameras, a printer gradation table memory 106 for storing gradation characteristics per type of printers, a target gradation table memory 107 for storing target gradation characteristics determined every object mode, and a table editor 110 for editing the target gradation characteristics.