I want to digress here to explain how you can vary the size of the snowflakes. These ones, which are the size you get by increasing the noise square 3 times, are an average size which suit the image we are using. If you want bigger ones, with this same size image, resize the noise square to 400 by 400, or even bigger if you want enormous flakes. Follow the rest of the instructions but when you reach this point, select a square 300x300 in your snowflake image and crop to that size. The easiest way to do this is to double click on the geometric selection tool. In the dialogue box which appears, set top and left to 0, bottom and right to 300 and check Custom Size and Position. The right size area will be selected, and if you want to move it around to choose a particular area of your snowstorm, then select the mover tool (immediately above the selection tool), right click inside the selection and holding the right mouse button down, move the selection to where you want it. Then use Image>Crop to Selection to make your snowstorm the right size.

For smaller flakes you need less enlargement when you resize the noise image. Since you still need the 300x300 snow image this means your opening image, the black one you started with, has to be bigger. If it is 150x150 and you enlarge to 300x300 you will have doubled it in size and the flakes will be smaller than the ones we got here by trebling it. The density of the flakes is controlled by the Brightness/Contrast step. If you want more flakes, increase the brightness setting at that stage, for less, reduce the brightness.

Move on now the next page, where we shall make the individual frames which will make the snowflakes move in the animation.