This Kristen Stewart photo contains
boater, leghorn, panama, panama hat, sailor, skimmer, straw hat, fedora, felt hat, homburg, stetson, trilby, street, city scene, and urban setting.
There might also be
green beret, special forces, elite soldier, pith hat, pith helmet, sun helmet, topee, topi, dress hat, high hat, opera hat, silk hat, stovepipe, top hat, topper, and beaver.