1. An image processing apparatus, comprising: an imaging unit configured to capture an object image and generate information representing a RAW image; a first development unit configured to acquire the information representing the RAW image and develop the RAW image; a storage unit configured to store in a memory an image file of an image developed by the first development unit, and a RAW file which stores the information representing the RAW image directly as a RAW image; a second development unit configured to read the RAW file stored in the memory in a predetermined interval or in an idle state, and develop the RAW image to obtain an image having higher image quality than that obtained by the first development unit; and a reproduction unit configured to reproduce, if an instruction for starting reproduction of a certain image is given and the second development unit has not completed developing of the RAW image, the image obtained from the image file and developed by the first development unit and to reproduce, if the second development unit has completed developing of the RAW image, the image developed by the second development unit.