Abstract: Image data coded by a variable length coding module is output to an external R/W controller and an internal R/W controller. A determination module compares the amount of coded picture data to be recorded next with the amount of free space on an external recording medium. If there is enough free space, image data is written on the external recording medium. If free space is insufficient, subsequent image data is written into an internal memory. When image data is coded into variable length data, it is difficult to predict precisely a recording time of the external recording medium, which means that the external recording medium may become full before a desired amount of image data is recorded. However, image recording may be continued using the internal memory even after the external recording medium becomes full.

Abstract: Even if the digital camera is inexpensive without the function of reproducing images, it can effectively use a memory capacity and has the function of responding to quick image-capturing, and important images can be recorded with higher priority. The digital camera comprises a priority selection switch for selecting priority of an image, and information about selected priority is recorded in association with the image when the image is recorded. For example, priority is ranked on three stages of “important”, “normal”, and “memo”. When a recording medium for storing image data has an insufficient memory capacity, control is exercised such that an image with priority lower than a newly captured image is automatically erased to record the new image. Further, a recorded image may be analyzed to automatically assign a low priority value to an image that may be damaged.

Abstract: A digital camera includes a shutter button. An optimal compression ratio of an image signal fetched in response to a photographing instruction from the shutter button is predicted prior to the photographing instruction. More specifically, an image signal fetched before application of the photographing instruction is compressed by a JPEG codec, and the optimal compression ratio is predicted based on a size of a compressed image signal thus obtained. An image signal fetched in response to the photographing instruction is compressed on the basis of the optimal compression ratio, and a compressed image signal thus obtained is recorded onto a recording medium.