Compliance with HelenaLC/SpatialData

[Artur-man]

ImageArray should potentially replace and comply with ImageArray-class under https://github.com/HelenaLC/SpatialData

https://github.com/HelenaLC/SpatialData/blob/02793581a80700da50bc605b96ff13f27af2d4c8/R/AllClasses.R#L11-L14