A method of processing a multi-layer image file (100) comprising a first plurality of image layers (106-108), and a second plurality of control blocks (120-122) is disclosed. The processing produces an animation sequence. The method comprises processing an image layer (eg 106) in accordance with a corresponding control block (eg 120), thereby providing an image for said animation sequence. The method further comprises tagging the image layer (106) for reprocessing, if the image layer (106) is to be used again in the image sequence, said tagging using a relative address referred to one of (i) an address of said corresponding control block (120) and (ii) an address of a control block corresponding to another image layer.