The kicker is that some of these models used to be able to do this. The only work around I've found is setting up a copy of the printer. This only works for a limited time though -- seems like the software catches on and forces you back to small phot...
I'm not if this will universally work, but I was able to get around this limitation by adding a "copy" of the printer. The copy of my TS 300 has a limited "printer preferences" menu where I can choose (and actually print) Letter + Glossy. I did this ...