A method for encoding images includes decoding a first encoded image to obtain a first decoded image, where the first decoded image includes a first decoded portion corresponding to a first encoded portion of the first encoded image and a second decoded portion corresponding to a second encoded portion of the first encoded image; decoding a second encoded image to obtain a second decoded image; combining the first decoded image and the second decoded image to obtain a single decoded image; and encoding the single decoded image to obtain a single encoded image that includes a third and a fourth encoded portions. Encoding the single decoded image includes obtaining the third encoded portion of the single encoded image by copying the first encoded portion of the first encoded image; and obtaining the fourth encoded portion of the single encoded image by encoding the second decoded portion using an encoder.