In this guide, we’ll show how you can do this by using the different selection tools available in Preview. Bear in mind, Preview’s solutions for removing backgrounds are basic, and they only work for simple and high-contrast images. That said, let’s get started.
Option 1. Use Instant Alpha
Instant Alpha is a selection tool based on color. In simple words, it scans the areas that you drag the cursor on and selects similar colors (because all objects are colored differently).
Here’s how you can use Instant Alpha in Preview:
Open the image you want to edit using Preview. On the toolbar, click the Show Markup Toolbar button, and the editing menu will open up. There’s a lot that you can do here to edit your image apart from removing background, so be sure to check out our Preview image editing guide. Then, click the Instant Alpha button located on the left of the toolbar. Now, start dragging the cursor to select the background. The red highlight predicts the area that will be selected once you release the click. Once the area is selected and a selection is made, press Delete to remove it. You may be prompted to convert the image to PNG, if it’s JPEG. Click Convert to proceed. Once the background is deleted, press Cmd + S to save the file.
Continue this procedure until all or most of the background is removed. The Instant Alpha feature will not work for images that have low contrast between the background and the object.
Option 2. Use the Rectangular and Elliptical Selection
The Elliptical and Rectangular Selection tools are best suited to situations where you want to crop rectangular or circular objects. Here’s how you can use these tools:
Open the image that you want to remove the background for in Preview. Click the Show Markup Toolbar button from the right. Click the Selection Tools button on the left, and a drop-down will open up. Here, choose from either of Elliptical and Rectangular Selection tools. Now, select the object that you want to crop, and press Cmd + X. Once the object is cut from the frame, press Cmd + A to select the remaining background and then hit Delete to remove it. Finally, press Cmd + V to paste back the initially displaced object and press Cmd + S to save the file.
Option 3. Use the Lasso Selection
The Lasso Selection tool allows you to form any shape by moving your cursor. Here’s how you can use this tool to remove the background from images in Preview:
Open the image you want to crop the object from. Click Show Markup Toolbar on the left, and then click Selection Tools > Lasso Selection. With this tool, click and drag to draw around the area that you want to crop out or delete. Hit Delete to remove your selection.
Although Preview suggests that the Lasso Selection tool can help you crop out any object from any background, it’s hard to trace the object perfectly in one go. Still, you can select and delete section by section, if you’re not looking for something perfect.
Option 4. Use the Smart Lasso
Perhaps the best trick that Preview offers is to remove the background is the Smart Lasso tool. Smart Lasso is a combination of Instant Alpha and Lasso Selection tools.
To use it, open the image you want to edit, select Smart Lasso from Selection Tools in the Markup Toolbar. Now, to remove the background, click and drag to outline an area by the border of the object you want to crop out.
When you release the mouse, a selection will be made depending on how well you outlined it. Delete this selection, and repeat the process until you’ve completely isolated the object.
There’s More to the Preview App
The Preview app on Mac may not seem like a good picture editing tool at first, but it is a hidden gem. By using its various selection features, you can remove backgrounds, and even add more objects to them. However, if you need a smarter and more efficient tool, consider using a third-party image editing app for your Mac.
