Okay, it does look like that you´re bf is low, but as suspected, there is some water between the skin and muscle. Since you´re doing this just because you wan´t to take a couple of pics, here is what i would do: start taking the otc diuretic, up you´re water to about 5-6 litres a day, train and do cardio normally, then after 5-6 days, lets say friday night stop drinking, but keep taking the supplement. When you wake up on saturday take a diuretic serving and eat a good meal like oatmeal and eggs, when you have about 3-4 meals in (without any liquids), pump up good and take you´re pics, this would be around 6 pm saturday. After you have taken you´re pics drink plenty of water and get plenty of minerals in too (salt). On sunday drop the diuretic and resume drinking normally 3-4 litres a day. When you drink more than you normally do and ad the supplement, you´re body will start to flush the water and continue to do so on saturday. I think that this way you´ll get great results. You may expirience a slight "rebound" effect on monday-tuesday (you´re body might hold on a little more water earlier on the week after the pics, but by wednesday you should be back to normal or a little better!)
Good luck!