cute idea!! I love doing mushy things like that, I always put a little note on his napkin in his lunch bag and usually one in the pocket of the pants I pack in his overnight bag. He'd love the picture in the thermos -- I'd have to surprise him with it, otherwise he might worry about taking it out in front of those senior CAs he's always flying with
They already tease him about my packing - "jeeze, she likes feeding you, doesnt she?!" (and here I am asking what else I can put in his bag)