It’s extremely easy to make an image transparent with the help of Preview app, the built-in image editing app that comes along with all Macs with Mac OS X. Do note creating transparent PNG or GIF images this way works best on images with uniform colors in the area you want to become transparent. The more complicated the image and color variation, the more work you will need to do with the alpha tool to make a portion of the image transparent.

How to Make a Transparent Image on Mac with Preview

You can turn any image transparent with Preview, though you’ll find the resulting image must be saved as an image format that supports transparency.

Open the image in Preview Click the Toolbox icon in the toolbar of Preview app to reveal the image editing tools

For earlier Mac OS X Preview versions: Click the little pen icon in the toolbar to reveal the image editing tools

Select the “Instant Alpha” tool, which looks like a magic wand in the Editing Tools menu bar (in earlier Preview versions it is contained under the Selection pulldown menu if the image is smaller than certain widths)

Click and hold on the part of the image you want to turn transparent, and while still holding move the cursor up or down to either select more or less of the image to turn transparent – anything that is red is what will become transparent

Hit the Delete key, or go to the Edit menu and select “Cut” to remove everything that was highlighted red with the Alpha tool (note: if the original image was a format that does not support transparency, you will be asked to convert the document, choose “Convert” to proceed” as expected

Repeat as necessary for other parts of the image you want to become transparent

To get the finer details transparent it can help to zoom in and out of the image using Command+Plus and Command+Minus keys.

If the original file was a PNG or GIF and you are satisfied you can just save as usual, but in a lot of cases you may not want to overwrite the original file. Instead, you can save the newly transparent image as a copy by using “Export” or “Save As”.

Exporting the Image as a Transparent PNG or GIF

PNG files are much higher quality than GIF, and for most uses you’ll want to use a transparent PNG, but we’ll cover both how to create and save as either transparent GIF or PNG anyway.

Saving a Transparent PNG

Go to File and choose “Export”

Select “PNG” from the pulldown menu, and check the box next to “Alpha” to insure the image maintains it’s transparency

Save as usual, maintain the .png file extension

Saving as Transparent GIF

Go to File and select “Export”, then Option-click on the file formats menu to reveal “GIF” as an option

Check the box for “Alpha” to preserve the image transparency, then save as usual with a .gif extension

Because you’ll need to perform manual adjustments with the alpha tool, this would not work on a group of files, though you could batch convert them ahead of time to PNG or GIF, then open each individually to make them transparent.

The video below walks through the process of turning an image into a transparent version of itself, including cleaning up areas that didn’t get immediately grabbed by the alpha tool by using zoom. This is demonstrated in an earlier version of Preview where the Editing Tools button was the Pen rather than the modern Toolbox icon, otherwise all else is the same:

You can make transparent images in Preview for Mac with nearly any version of the app this way, whether you’re in a modern macOS release, or an earlier Mac OS X version, the Preview app can create transparent gifs and transparent PNG files easily. Just remember to look for the Toolbox button in modern Preview versions and the Pen button in earlier Preview releases.