Change a slide background in Keynote on Mac
You can change the background colour or image of individual slides in a presentation.
In the Format sidebar, click the disclosure arrow next to Background, then choose one of the following:
A colour designed to match your theme: Click the colour well next to Background, then select a colour.
Any colour: Click the pop-up menu and choose Colour Fill, then click the colour wheel to open the Colours window, where you can choose any colour.
A two-colour gradient fill: Click the pop-up menu and choose Gradient Fill, then choose colours. The left side of the colour well shows colours that match the theme; the colour wheel opens the Colours window, where you can choose any colour.
A custom gradient: Click the pop-up menu and choose Advanced Gradient Fill, then click the colour stops below the slider to choose colours. You can slide the colour stops and use the other controls to change the blend, angle and direction of the gradient.
An image: Click the pop-up menu and choose Image Fill, or choose Advanced Image Fill if you want to add a tint to the image. Click Choose, navigate to your photos, then double-click an image to add it. To change how the image fills the background, click the pop-up menu above the Choose button, then choose an option:
Original Size: Places the image without altering the image’s original dimensions. To resize the image, drag the Scale slider.
Stretch: Resizes the image to fit the slide’s dimensions, which might change the image’s proportions.
Tile: Repeats the image on the slide. To resize the image, drag the Scale slider.
Scale to Fill: Makes the image larger or smaller to leave no space around the image.
Scale to Fit: Resizes the image to fit the slide’s dimensions, but maintains the image’s proportions.
If you chose Advanced Image Fill, click the colour well or colour wheel to select a tint colour. Adding a tint makes the image more transparent.
To change the background of all the slides that use the same master slide, apply the change to all slides that use the master.