Step 8. Click on the frame of the snow image to make it current and copy it to the clipboard. (Either Edit>Copy or use the copy button). Click on the new image and paste a copy of the snow into it on a layer. (Either Edit>Paste>As New Layer or use the paste as new layer button). Arrange the layer so that this copy exactly fills the bottom half of the image. Paste a second copy on another layer and arrange that at the top of the image, which will now look like the one on the right. Make certain that there are no gaps at either side or where the images meet. If there are, use the mover tool and slide the layers to exactly the right place.

PLEASE NOTE that this illustration is half size - as the image looks if zoomed to 1:2. Use Layers>Merge>Merge Visible.

You now have a snow image the same width as your graphic image and twice as high, with one layer on the layer palette called Merged. Save this new image and close the original one which you have just copied.

Step 9. Add a layer to the snow image (Layers>New RasterLayer) and make sure in the Layers palette that it is now the selected layer. If the image is zoomed out to 1:2, zoom in to 1:1 (Hit the + key on the keypad once). Scroll the image so that the whole of the bottom half of it is visible in the window.

Change the foreground colour to a colour clearly visible against black and white. (Click in the foreground colour displayed on the right of the screen and select a suitable colour. I have used bright green)

Select the shapes tool. It is the last but one tool, a red ellipse on top of a blue square. In the Tool Options set Shape Type>circle, Style>Stroked, Line Width>1, Antialias checked and Create as vector unchecked.

At the bottom left of PSP's window, just above the START button, you will see the two co-ordinates for the cursor position. These change as you move the cursor about the screen. Place the cursor in the image and move it till the co-ordinates read 150,450. This is the exact centre point of the bottom half of the picture.

Step 10. Left click and drag outwards till the co-ordinates outlined in red in the illustration are as near to 250,250 as you can get them. Mine would go to either 249 or 251, but not exactly 250. But since this green circle on the new layer is only a guide, total accuracy is not important.

If you find that when you press the mouse button the cursor moves away from 150,450, try using the mouse like a trackball. Pick it up and move the cursor by moving the ball at the bottom of the mouse with your fingers. When you have it in position, take your fingers off the ball and check that you did not move the cursor while doing that. Once you have the cursor fixed in the right position, keep the mouse in your hand and without touching the ball press the left button. Once you have pressed it you can keep it held down and put the mouse back on the mouse mat for the dragging part of the operation.

Step 11. Scroll the snow image till the whole of the top half is visible. Set the cursor at co-ordinates 150,150 (the exact centre of the top half of the picture) and then repeat step 10. Again my circle size was 251,251. You now have two circles in the top layer of your snow image. If you inspect them closely you will see that the snow pattern they contain is identical. I have marked some points of comparison in the illustration below.

These identical patterns are important because if an animation is to be smooth the pattern must flow naturally from one frame to the next. Our first frame will be the bottom circle (if we start at the top the snow will fall upwards). Each frame will be exactly the same vertical distance apart, and our last frame will be the one before the top green circle. The animation will be smooth because after the last one it will play the first frame again, and that is identical to the one which would have come next in the progression.

On the next page we begin to make the frames.