1. An image capturing apparatus comprising: an image sensor in which pixels including pixels in a correction pixel region and an effective pixel region are arrayed two-dimensionally and which outputs uncompressed or losslessly-compressed effective pixel region image data acquired from the effective pixel region and uncompressed or losslessly-compressed correction pixel region image data acquired from the correction pixel region; a processor which resizes the effective pixel region image data; and a controller which controls the processor not to resize the correction pixel region image data in a case where the processor resizes the effective pixel region image data, and controls the processor to generate an image data of one frame by combining the resized effective pixel region image data with the non-resized correction pixel image data; and an output circuit which outputs the image data of one frame outside of the image capturing apparatus.