Publishers often require ads to have a one-pixel contrasting border.
Add a border when publishing the ad
When you publish an ad in Google Web Designer, the publish dialog gives you the option to add a border and pick the border color.
Add a border while building the creative
If you want to build the border into your creative before publishing, you can create a div, give it a border, and make sure it all fits inside the ad.
- Select the Element tool from the toolbar and click the Div element icon on the tool options bar. Make sure the Background color is set to No color.
- Draw the div as a rectangle from the top left corner (position 0,0), then open the Properties panel and set the width and height to 100% so the div is the same size as the page.
- In the Style section of the Properties panel, set the border color so that it contrasts with the ad's background color, and set the border size to 1 pixel.
- Open the CSS panel and add the property
box-sizing: border-boxin order to keep the border inside the div.