The method compresses image data into a fixed sized memory. The image is encoded in scans, where the scans are ordered from a perceptually most significant scan to a perceptually least significant scan. The scans also have an attribute 210 determining whether a scan is active or inactive. The method comprises an encoding, transferring and setting step. The encoding step 326, 348 encodes active scans of image data into scan bit-stream data. The transferring step 330, 352 transfers the encoded scan bit-stream data to the fixed size memory. The setting step 452 sets, if the fixed size memory becomes full, the attribute of a perceptually least significant scan to inactive.