Step 1: Navigate to a slide that you want to update the image on. Click on the "Slide" drop-down and then find you can use the multiple different sections depending on what you are updating.

You can select from a video background, the images, or any of the popup options from this menu.

Step 2: After selecting the content that you are trying to update, a new window will pop up where you can change the video or image. You can either upload from your computer or find a file from your library.