1206 i believe. you can always measure em with a caliper or micrometer.
0603 = 0.06" X 0.03"
0805 = 0.08" X 0.05"
1206 = 0.12" X 0.06"
The resistors in ur pic are definately 0805 so i think the LEDs are the next size up(1206). but 0805 LEDs will fit on 1206 pads if thats what u got, may even be easier to solder by hand cuz more pad will show.