1. A digital still camera comprising: a solid-state electronic image sensing device for sensing the image of a subject repeatedly for an exposure time over which camera shake is thought not to occur, and repeatedly outputting image data representing the image of the subject; a combining device for generating one frame of a combined image obtained by combining the image of the subject represented by image data that has been output from said solid-state electronic image sensing device with the image of the subject represented by image data that was output from said solid-state electronic image sensing device by an immediately preceding image sensing operation, in such a manner that the images of the subject coincide; a combining control device for controlling said combining device so as to repeatedly execute processing for generating one frame of a combined image updated by combining the combined image, which is the result of combination by said combining device, with the image of the subject represented by image data that has been output from said solid-state electronic image sensing device, in such a manner that the images coincide; and a recording control device for recording, on a memory card in response to an exposure-halt command and on the basis of timing at which the exposure-halt command has been applied, image data representing the combined image updated in the processing in said combining device that is based upon said combining control device; wherein said solid-state electronic image sensing device senses a first plurality of frames of images of the subject after the exposure-halt command is applied; further comprising a temporary memory for temporarily storing the image data, which is repeatedly output from said solid-state electronic image sensing device, of a second plurality of frames of image data that is greater than the first plurality of frames, and said second plurality of frames further includes the first plurality of frames; wherein said recording control device records the second plurality of frames of image data, which has been stored in said temporary memory, on the memory card in addition to the image data representing the updated combined image.