An image-data-processing device for processing first image data includes an image processing chip with a first memory and a second memory. The image processing chip further includes a data managing unit and a coding module, wherein the memory space of the second memory is greater than the memory space of the first memory. The data managing unit receives the first image data from an image sensor and transmits the image data to the encoding module, wherein the encoding module generates a second image data based on the first image data received. The data managing unit then selectively stores the second image data in the first memory or the second memory.