Image processing apparatus and image reproducing apparatus

Disclosed is an image processing apparatus capable of storing composite image data and reconstruction information of original image data used for computing operation to generate the composite image data in a state where both of the data is always associated with witch other. The format of a composite image file is divided into a tag area, a captured image recording area, and a thumbnail image recording area in which attribute information, a composite image, and a thumbnail image are recorded, respectively. Further, in the tag area, reconstruction information of the original image data used for computing operation to generate the composite image data is recorded. The reconstruction information has a pattern in which original image data is recorded as it is, a pattern in which differential data between the original image data and composite image data is recorded, and a pattern in which differential data between the original image data and another original image data is recorded.