How to mask an image in Keynote on Mac: three methods, step by step

Before you start: check your Keynote version

Apple's What's New notes for Keynote 15.1, 15.3 and 15.4 list no changes to masking or the Format menu. Apple's Mac help page on editing images does not name a version, so these steps rest on those notes. Check your version under Keynote > About Keynote.

The version question matters for one reason. Keynote 15.4 requires macOS 26 Tahoe, according to TidBITS, and Apple says Keynote generally needs macOS 26 or later. If your Mac runs an older system, the menus you see may not match the ones described here.

Three ways to mask an image in Keynote

Keynote gives you three masking routes on the Mac. A mask hides part of the photo instead of cutting it away. That means you can adjust the frame later by double-clicking the image again.

Method 1: crop the image with the double-click mask

This is the method most people need. Double-click the image and Keynote shows the mask controls. Apple also lets you Force Click on a Force Touch trackpad to open them. Then frame the part of the photo you want to keep and click Done.

1. Click the image once to select it.
2. Double-click the image, or Force Click on a Force Touch trackpad, to show the mask controls.
3. Drag the picture until the part you want sits inside the frame.
4. Drag the frame's selection handles to resize the visible area.
5. Click Done to keep the mask.

The mask controls behave like a crop tool with a fixed frame. You move the photo under the frame, and everything outside stays hidden. Say your slide shows a group photo, and you only want the speaker. Double-click, drag until the speaker sits inside the frame, shrink the frame, then click Done.

Method 2: mask with a preset shape in Keynote

Use this method when you want a standard outline instead of a rectangle. Select the image, then choose Format > Image > Mask With Shape from the menu bar. Keynote places a shape over the photo. Pick a shape from the options, and drag its handles to size it.

A simple outline usually suits a headshot better than a busy one. Choose a shape that fits the slide's look, then size it so the face sits near the center. Keep an eye on the edges, because a tight frame can clip hair and hands.

Method 3: mask with your own drawn shape

Choose this when no preset shape fits. First, draw the shape you want on the slide. Then Shift-click the drawing and the image so both are selected. Choose Format > Image > Mask with Selection, and drag the handles on the drawing to set its size.

The photo takes on the outline of the drawing, so the drawing matters more than the photo. Draw a closed shape with clean edges, and check the result at full size. A rough outline gives you a rough edge.

Keyboard shortcuts for masking in Keynote

Apple's Mac page lists no keyboard shortcuts for masking. The modifier keys below come from the steps. Hold the key while you click or drag, and the action changes.

• ⇧ click: select a drawn shape and the photo together for Mask with Selection.
• Force Click: open the mask controls on a Force Touch trackpad.
• ⌥ drag: remove one color everywhere in the Remove Background tool.
• ⇧ drag: add color back where you removed it.
• ⌥ click: reset a masked image before you replace it, based on a community reply.

Remove Background is a different tool

Remove Background does not mask. It removes areas of color from the photo itself, which helps when a person or logo sits on a plain background. Select the image, open the Format sidebar, click the Image tab, then click Remove Background.

Drag over a color to remove areas like it. Option-drag removes that color everywhere in the photo. Shift-drag adds color back. Reset undoes all of your changes, and Done finishes the edit.

Auto Crop needs a Creator Studio subscription

Auto Crop suggests crops for you. Double-click the image, click Auto Crop, click the suggestion you like, then click Done. Apple's help page says the feature requires an Apple Creator Studio subscription.

Apple lists Creator Studio at $12.99 a month or $129 a year in the U.S. MacRumors reports that Auto Crop is one of the subscriber-only Keynote features. Apple's masking page names a subscription only for Auto Crop, so the other methods are not listed as paid features.

Keynote for iCloud masks work a little differently

In Keynote for iCloud, double-click the image to show the mask controls. Use the slider to scale the picture, drag to shift it, and drag the selection handles to resize the mask. Click Done when the frame looks right.

To restore the original size, select the image, click Arrange at the top of the Format sidebar, then click Original Size under Size. Apple lists no keyboard shortcuts for cropping in this version.

Apple's iCloud help page does not mention Mask With Shape, Mask with Selection, Remove Background or Auto Crop. That is an absence on one page, not proof those tools are missing. Check the web version yourself before you plan a deck around one.

Mistakes people make with masked images

• Selecting the slide background instead of the photo. Click the picture itself before you open the Format menu.
• Trying to mask two photos with Mask with Selection. The command needs one drawn shape and one image.
• Forgetting Done. Click Done to close the mask controls and keep your change.
• Replacing a masked image before the final version is ready. A replaced image can arrive at the wrong size.
• Expecting Remove Background to behave like a mask. It erases color, so check the photo at full size after each change.

When Mask with Selection grays out

A 2022 Apple Community thread on macOS 12.2 describes the same problem on a MacBook Air with an M1 chip. The poster selected two JPEG images, and Mask with Selection grayed out or went missing. The most helpful reply says one object must be a shape, not an image. The thread closed without a confirmed fix, so the M1 explanation is only a guess.

Draw a shape, Shift-click it with the photo, and try the menu again. If the command still does not appear, use Mask With Shape instead. That method sits in the same Format > Image menu and does not need a second object.

Replacing a masked image without losing the frame

A 2020 to 2021 Apple Community thread on macOS 11.6 describes a replaced masked image that comes in smaller. The suggested fix is to Option-click the image to reset the mask, choose Replace Image from the image palette, then remake the mask. The original poster did not confirm the fix worked, so test it on a copy of the deck first.

After you mask the image

Check the masked image in a slideshow before you present. Choose Play > Play Slideshow to see the slide the way your audience will. Press ⌥⌘P to start the show from the keyboard.

If you want the masked photo to appear on click, add an animation. Animate an object in Keynote on Mac walks through the steps. Set the mask first, then animate it, so the timing matches the final frame.

Next steps for your slides

If the photo sits on a repeated design, set up the layout first. Edit the master slide in Keynote on Mac covers how layouts work, so each new slide starts with the right frame.