Photos for Grandma's main window is a repository for smaller contacts' floating windows.
Here you can browse through contacts using arrows, add new contacts, edit or delete them, but you can also start the sending process. To do that click Add on a contact's floating window and make a selection of photos to send. Then you can check the selection by clicking View or proceed with sending by clicking Send.
Pay attention that you can drag any contact's floating window out of the main window frame and keep it on the desktop for direct access.