First, the picture is
fake. It is a composite photograph compiled for a motivational poster.
Second, ice will float with 8.7% of the ice above water. Calculation is like this:
density of water (at 4 degrees celcius -- the densest temp. for H20): 1.0 g/mL
density of ice (at 0 degrees celcius): 0.92 g/mL
1.0 / 0.92 = 1.0869... or 108.7%
in other words, the same mass of liquid water occupies 108.7% of its original volume when frozen.
Since we are being geeks here, think about this: Water/ice is the only substance that expands when it freezes. All other substances occupy less space when it is a solid then when it is a liquid and are therefore more dense when a solid. If this were the case with water, lakes would freeze solid in the winter since as the surface freezes it would sink and allow more ice to form and sink... and so on. This unusual property of water allows life to survive in lakes that have frozen over since the layer of ice protects the deeper water from freezing.