1. An image processing method comprising: calculating flash-component image data based on first image data captured by an image capturing unit without flash emission and second image data captured with flash emission; calculating an intensity adjusting value for the flash-component image data by an intensity-adjusting value calculating unit; calculating intensity-adjusted-flash-component image data by using the intensity adjusting value; and generating adjusted image data by an adjusted image generating unit based on the first image data and the intensity-adjusted-flash-component image data; wherein calculating the flash-component image data further includes calculating differential image data representing differences between the first image data and the second image data, and executing white balance control on the differential image data based on a parameter corresponding to the flash emission; and wherein the intensity adjusting value for the flash-component image data is calculated using the differential image data.