Classes to convert JIU image objects to other image types that require more memory.
This is a lossless operation, all information is kept.
However, the new image object typically requires more memory to store the same information.
A promotion operation is necessary if a certain operation cannot be performed on
a smaller
image type, but once the image has been promoted to a larger
type, the operation becomes possible.
Example: Convolution kernel filtering cannot be applied to paletted images. They require intensity information on each pixel. Once a paletted image has been promoted to be an RGB truecolor image, filtering is possible.