Basic clipping masks

Clipping masks are helpful for bold effects like this, but also for more simple image-editing tasks like filling a phone screen with an image (we used a free Photoshop template here, go to File > New, click the Mobile tab and download an image). We simply select the phone screen area, make a new layer and fill in the selection using any colour, then copy in our image and clip it to the screen layer. This confines the image to the screen area, while still giving us the freedom to change the position of the image within the frame.