Over the Christmas holiday I collected some background photos of winter trees with bare branches. I wanted to use these photos to combine with other images. The picture below is one of the first uses. It shows a forest edge at sunset combined with three other photos.
To create an image like this I start with a portrait of a model lit with highly defined areas of dark and light. The background is completely white. The model is dressed in black and is lit with a dark shadow on the side of her face near the camera. The mode of this layer in Photoshop is changed to "Lighten". That means that everything below the image that is lighter than the model image would shine through. That gave me the sunset trees coming through the black areas of the model image. To soften the tree image down a bit I put another photo of a cloudy sunset on top of it, changed its mode to "Lighten", and dialed down its opacity.
I added a Vibrance Adjustment layer and attached it to the model image. This allowed me to dial down most of the color in her face. Lastly, I added the photo of the gulls over the ocean on top of the model image and changed its mode to "Darken" which allowed the model photo to pass through its dark areas.