Well, I've done a small calculation.
Very simple method, the picture your trying to click has an almost size of 700 X 765, meaning the total number of pixels is around 535,500
The maximum number of prizes is 45.
So, 45 pixel are the only pixels out of the 535,500 other pixels that contains a gift.
45/535,500 = 0.000084
Meaning, if you want to know what is your chance out of hundred to win,
it is 0.0084 out of hundred.
For those whom already won, you where very lucky
For others playing, now @ the moment, the prizes are 33,
So the chance is obviously lot less, Good Luck.