protected void decodeExtendMarker(int marker) throws IOException {
int length = in.readUnsignedShort();
length -= 2;
ExtendImageHeaderReader reader = extendImageHeaderReaders.get(marker);
if (reader != null) {
reader.readProperties(in, length, extendImageHeader);
} else {
if (length > 0) {
in.skipBytes(length);
}
}