1. An image capturing apparatus comprising: an image capturing unit configured to capture an image of a subject by using an image sensor having pixels each including a plurality of receiving elements, and to generate signals corresponding to each of the plurality of the receiving elements; a generating unit configured to generate a first RAW image and a second RAW image from the signals; a first development unit configured to generate first image data by performing development processing on the first RAW image; a RAW compressing unit configured to generate first compressed-RAW image data and second compressed-RAW image data by compressing the first RAW image and the second RAW image; and a second development unit configured to perform development processing on the first RAW image, the development processing performed by the second development unit having a higher processing load than the development processing performed by the first development unit, wherein the second development unit generates second image data by performing development processing on the first RAW image by using the second RAW image.