rast(ncols=600, nrows=600, nlyrs=3, xmin=0, xmax=10000, ymin=0, ymax=10000, names=c('tissue_lowres_image_1', 'tissue_lowres_image_2', 'tissue_lowres_image_3'), crs='')

rast(ncols=2000, nrows=2000, nlyrs=3, xmin=0, xmax=10000, ymin=0, ymax=10000, names=c('tissue_hires_image_1', 'tissue_hires_image_2', 'tissue_hires_image_3'), crs='')