Option 1: When you have your basic overlay and are looking to upload a background image select the background and head here:
Option 2: If you want to make the pre engagement and post engagement different images separate the images and insert a pre and post image!
Option 3: Inserting an image to your overlay that isn't a background image.
- Head to the add layer section on the left hand side of your canvas and hit the image icon:
An image layer will be added to your canvas, simply drag the layer to the place you want on your canvas and find the background image button on the top of the design canvas to upload the image!