Thank you. I was finally able to switch the printer from main tray to photo tray. It requires an awful lot of mucking about, as it wouldn't work from the app's printing options and forced me to go into the Options submenu.
At any rate, I now know how to switch back and forth between the trays.
I have another issue (print quality bars have horizontal lines running through them and cleaning the cartridges does not fix it and in one case even made it worse). I will look in other threads to see if there is a solution to that. If someone could point me at a thread to start, that would be great.
Thanks.