1. A method of generating an attribute map for processing an image, the method comprising: receiving an image encoded into a plurality of segments, each segment being characterised by a position within a base region associated with the image and being encoded according to a corresponding encoding format; decoding a segment from the plurality of segments into a sub-image, the sub-image being associated with a combination operation and an attribute value derived based on at least one of a segment decoding format and a segment encoding format, the combination operation determining a process of combining the sub-image with the underlying base region; determining an information-carrying pixel value in the sub-image based on the sub-image pixel content and the attribute value associated with the sub-image; and generating the attribute map for processing the image, the attribute map being generated using the attribute value associated with the sub-image for at least one pixel of the attribute map.