I first downloaded a horse and landscape photo and opened them in photoshop with the landscape above the horse. I turned the opacity of the landscape to about 50% and repositioned it until the landscape somewhat lined up with the horse's markings. I then turned the opacity of the landscape back up to 100% and hid that layer. I then selected the horse, copied and pasted that selection into the landscape layer, clicked select➡inverse➡delete, then put a layer mask on the landscape layer and, hid it, then drew over it with a brush at ~50% opacity until I liked the result.