Cropping is useful for excluding unwanted content at the edge of a photo, changing the shape of a photo for a particular use, or improving image composition by reframing a photo. Cropping in Lightroom is not permanent and can be modified at any time.
Crop a photo
When you activate Lightroom’s Crop tool, a crop boundary appears around the edge of the photo where you can change the size and shape of the photo. You can also move the photo around within the crop boundary to choose the part of the image you want to keep or crop away. The crop boundary in Lightroom includes an overlay that lets you reframe the image to take advantage of the Rule of Thirds, which has been used for centuries to improve composition in art.
Change the aspect ratio or shape of the crop
Aspect ratio means the proportion of width to height or vice versa. The aspect ratio of a crop boundary determines the shape of the cropped photo. For example, a 1:1 aspect ratio defines a square crop. Don’t confuse aspect ratio with dimensions. A 1:1 square could be 10 pixels by 10 pixels, or 100 inches by 100 inches.
If you know that you want to crop to a standard aspect ratio, like 1:1 or 4:5, choose it from the Aspect Ratio menu in the Crop panel. This causes the crop boundary to maintain those proportions, no matter how big or small the boundary becomes as you drag its edges.
Straighten a crooked photo
If a photo is slightly crooked, you can correct it with the Straighten controls in the Crop panel. Sometimes all you have to do is click the Auto label above the Straighten slider. If you don’t like that result, you can adjust the rotation manually with a slider in the Crop panel or by dragging outside a corner of the crop boundary in the direction you want to rotate the image.