An imaging apparatus comprises an imaging device to take an image, a device to create a main image by resizing a main image before compressing imaged by the imaging device, and then by compressing to a fixed length, a device to create a reduced image for display by resizing to reduce the main image before compressing, and then by compressing the reduced main image before compressing, a device to estimate a most appropriate compression parameter for compressing the main image before compressing, which is resized to create the main image, in the proximity of a target size based on a data created by the device to create a reduced image for display, and a compression device to obtain a most appropriate compression rate based on the most appropriate compression parameter, and then to compress the main image before compressing to the fixed length by the most appropriate compression rate.