How to use IMAGEDATASTORE for Lables that are a matrix or image

Hello I'm trying to use non-categorical labels, not like Labels [1 2 3..]. I want to use labels in a form of an image, such as a density map. Can someone guide me how to use

digitData = imageDatastore(fullfile(rootFolder),'LabelSource',fullfile(rootFolderD));

where rootFolderD contains density images of size 32x32