Kodak is rumored to announce a new smartphone on October 20th. As the website Ubergizmo noted, the big button on the leaked picture/teaser could be a dedicated shutter release:
"Safe to say that its specs and features are really anyone’s guess right now, but given Kodak’s ties to the photography industry, perhaps we’ll see features that are more photo-centric. Heck, even the teaser image above seems to indicate some kind of button that could maybe be a dedicated shutter release, who knows?"