An image (1) is decomposed into multiple superblocks (20, 22), each encompassing multiple pixel blocks (30A-30D, 32A-32D) having multiple pixels (40). The property values of a superblock (20) is fixed rate compressed to get a compressed block having a target bit length. The compressed block is stored in the memory locations (310, 320) assigned to the multiple pixel blocks (30A-30D) encompassed by the superblock (20) to thereby get multiple copies of the compressed block in the memory (300). The multiple copies collectively constitute a compressed representation of the superblock (20). When accessing a compressed block in a memory location (310) using random access during decoding, property values for neighboring pixel blocks (30B-30D) are obtained for free without the need for any further memory access.