An image-capturing device includes: an image sensor that captures an image of a subject to output an image-capturing signal; a development processing unit that generates development data based on the image-capturing signal; and an output control unit that outputs the development data to an external device in a predetermined transmission format via a connecting member that connects the image-capturing device to the external device. The output control unit outputs the image-capturing signal to the external device via the connecting member in the predetermined transmission format.