With macOS Preview, you can do more than just view photos. You can easily and quickly remove the background from a photo. Explanation.
The Preview app on macOS is more than just a document viewer. In particular, it has many image editing features that can help you perform a number of relatively complex operations, including removing elements from the background or the entire background of your photos.
How to remove the background from an image in Preview
On any image that’s open in Preview on your Mac, click the pencil icon in the action bar – to the left of the search box – to open the toolbar just below the search box. Then select the Instant Alpha tool (second from the left, which looks like a magic wand); you can then hover over the background of the image. Click and move the cursor over the background to view the selection in real time, and release the cursor when you are satisfied with your choice.
Be careful, the tool is quite sensitive, if you move the slider too far, it may select the entire image, not just the background.
Now that you have your background selected, click the Remove button on your Mac keyboard to remove the background. You can repeat the operation to remove any remaining items if your original selection didn’t make everything disappear.
Tool Limitations
The Preview Instant Alpha tool does a surprisingly good job of removing the background from a whole bunch of images. That being said, you often need to fine-tune to get the right selection, and automatic selection can sometimes be inaccurate.
If you want to quickly remove the background from multiple photos in your library, Preview is perfect. But if you’re hoping to edit a large number of files, similar tools from applications like Adobe Photoshop and its alternatives are much better. In other words, the preview can get the job done when you need it spontaneously, but it’s far from ideal for higher level and/or volume editing.