Today were going to attempt to create a simplistic yet realistic rainy day. This is basically a beginner tutorial, and my first attempt at writing one, so stay with me here.We're going to try to reproduce the effect achieved in turning this image:into this one:First thing you need to do is open the picture you want to add rain to. You can use any picture you want, or you can use the one provided. Next, duplicate the background layer (CTRL+J) by either dragging the layer to the Create a New Layer button at the bottom of the layers pallet OR going to Layer > Duplicate Layer(this requires you to click OK).Heres the fun part! On your background layer copy go to Image > Image Adjustments > Curves (CTRL+M) and make your setting something like this: Or you can play around with them to get the desired effect you want. This gives the image that dark rainy day appearance.