The composition of a picture is almost as important as the lighting, exposure and colour balance. You may not realise it but almost every photograph that you see in a book, gallery or magazine will have either been framed meticulously when it was taken or, more likely, cropped manually afterwards. The reasons for cropping are numerous. For a start, you often need to centre your subject within the frame to make them the focus of the image. Or, you may need to remove an overhanging tree branch from an otherwise clean scene. In yet another example, cropping can be used to change the message given by a picture, for instance by removing a person from it, a trick that some tabloid newspapers are not averse to using. Luckily, cropping in Preview is easy enough to do. Read our step-by-step tutorial to find out exactly how it works…
Step 1: Choose a picture
Find a picture that could be improved by cropping and double-click to open it. It should automatically open in the Preview application.
Step 2: Select an area
Click the Select box in the toolbar. The default tool is the Rectangular Selection tool and if you click and drag round an area, you will see a marquee appear.
Step 3: Resize the box
Drag the handles at the corners and edges of the marquee to change its size. When you’re done, select Tools>Crop or press Command+K.
Step 4: Crop the picture
The area inside the marquee will be kept while the rest is discarded. Save the image under a new filename so as not to overwrite the original.
Step 5: Use a different tool
Take the original image, choose Elliptical Selection under the Select tool and select an area. You can hold the Shift key to constrain it to a perfect circle.
Step 6: Reposition crop area
Instead of dragging the resize handles at the corners and edges, you can drag from the centre of the selected area to reposition it.
Step 7: Crop the image
With your circular area selected, choose Tools>Crop as before and you will be left with a circular image rather than a square one.
Step 8: Use the Lasso
The Lasso tool can be used to draw custom selection areas. Click in the image and draw freehand around a shape, just like if you were cutting with scissors.
Step 9: Cut it out
Choose Edit>Invert Selection, then press backspace to erase everything except the area selected. This is a good way to cut things out in a freehand manner.