Screenshot: Pranay Parab
Preview is much more than a simple image viewer. Its image editing capabilities can actually help you accomplish slightly complex tasks—including removing unwanted backgrounds from your photos.
How to remove the background from an image in Preview
From any open any image in Preview on your Mac, click the pen icon in the top bar—located to the left of the search box—to open a toolbar below the search box. Select the Instant Alpha tool (the second one from the left); you can now move the cursor to the background of the image. Click-and-drag the cursor on the background to get a live preview, and release the cursor when you’re satisfied with the background selection.
Keep in mind that the tool is a bit sensitive—if you drag it too far, it can select the entire image, instead of just the background.
Now that you’ve successfully selected the background, press the Delete button on your Mac’s keyboard to remove the background. You may have to repeat the process once to eliminate the background completely if the original selection missed out on a couple of spots.
The limitations of Preview’s background removal tool
The Instant Alpha tool in Preview does a surprisingly good job of removing the background from all kinds of images. However, it requires a bit of fine-tuning to get the selection right, and its automatic selection can sometimes be inaccurate.
If you’re looking to quickly remove the background from a couple of images in your photo library, Preview is great. But if you’re hoping to edit a large number of images, the background removal tools in apps like Adobe Photoshop and its alternatives are much better suited to the task. In short, Preview can get the job done when you’re in a pinch, but it’s not ideal for professional editing.
