How to Add Snow to a Photo in Paint.NET
As odd as it may seem, you first need to create a new layer and fill it with solid black to produce the effect of snow. You’ll then combine the fake snow with the background layer to give an impression of the final effect:
Go to File > Open and select the image you wish to edit. Go to Layers > Add New Layer. Set the Primary color in the colors palette to black, then select the Paint Bucket tool either from the menu or the toolbar. Click on the image to fill the new layer with solid black. Go to Effects > Noise > Add Noise. Set the Intensity slider to about 70, set the Color Saturation slider to 0, and move the Coverage slider all the way to 100. You can experiment with these settings to get different effects. When you’ve applied your settings, select OK. Go to Layers > Layer Properties. Select the Blending Mode drop-down menu and select Screen, then select OK. Go to Effects > Blurs > Gaussian Blur. Set the Radius slider to 1 and click OK. For denser snow, go to Layers > Duplicate Layer. Alternatively, you can produce a more random result by repeating the previous steps to add another layer of fake snow. You can also combine different fake snow layers with different levels of opacity by changing the settings in the Layer Properties dialog, which can help to give more natural results. Go to File > Save As to save the edited image.
