1. An image processing device comprising: a plurality of encoder circuits configured to generate a plurality of encoded bitstreams, respectively, the plurality of encoded bitstreams having different resolutions based on an original image, the plurality of encoder circuits further configured to generate a plurality of restored images having the same resolution as a first resolution of the original image using the plurality of encoded bitstreams, respectively; wherein a first encoder circuit of the plurality of encoder circuits includes a first internal-encoder circuit configured to generate a first encoded bitstream associated with the first resolution, and a second encoder circuit of the plurality of encoder circuits includes, a down-scaler configured to generate a down-scaled image based on the original image, the down-scaled image having a resolution different from the first resolution, a second internal-encoder configured to generate a second encoded bitstream from the down-scaled image, and the plurality of encoded bitstreams includes the first encoded bitstream and the second encoded bitstream; and and an output circuit configured to output one of the plurality of encoded bitstreams based on the plurality of restored images and the original image.