summary S3 method for ggbrain_images objects addition operator for combining ggbrain_images objects
# S3 method for ggbrain_images
+(o1, o2)combined ggbrain_images object
first ggbrain_images object
second ggbrain_images object
note that the addition does not modify either existing object. Rather, the first object is cloned and the second is added to it. If you want to add one ggbrain_images object to another in place (i.e., modifying the extant object), use the $add() method.