NoData may change across image operations.
Think about a DEM with floating point numbers (and noData = -9999) being rescaled to byte.
The nodata should be updated accordingly to the data type and the rescale operation should not map valid values to it.
In addition, with JAI-EXT enabled (supporting roi and nodata) some operations support remapping an input noData to a destinationNoData. The ImageWorker should update the NoData accordingly.