SpatialFeatureExperiment and the Voyager package work with
images differently from SpatialExperiment. In SFE and
Voyager's, plotting functions for SFE objects, the images can be read
with rast and represented as SpatRaster, so the image is
not entirely loaded into memory unless necessary. Plotting will not load a
large image into memory; rather the image will be downsampled and the
downsampled version is plotted. A SpatRasterImage object (as of Bioc
3.19 or SFE version 1.6 and above) is a SpatRaster object but also
inheriting from VirtualSpatialImage as required by
SpatialExperiment.