The Pinterest app lets users adjust photo contrast before posting it to the board. After snapping a photo, simply tap and drag your finger across the photo. Sliding up will lighten the photo while sliding down will darken it. Selecting an image from your camera roll gives you the opportunity to move and scale the photo to your preferred proportions before tapping and dragging. Choose an image and slide the image around to position it in the highlighted box. Users can also zoom in and out using pinch-zoom.