Google has made some updates to their Discovery ads. One of these updates is new 4:5 aspect ratio layouts. This allows images to be showcased more prominently in the Discovery feed.
This new image format recommends using images that are 960 x 1200 to really benefit. But you will still need to include one landscape and one square image for your ads. Google then selects one of the images based on a number of factors each time your ad is shown.
Google has also made updates to the audience selection workflow for Discovery campaigns. This includes estimating a conversion volume lift when audience expansion is turned on. Google will also be adding reporting for your audience expansion. This way you’ll be able to see the performance of the expanded audience next to your chosen audiences. This will be available at an ad group, campaign and account level.