To add image panels, hover the Add Panels button and select Image panels . The WordPress Media Loader will be opened, where you can select a single image or multiple images (by holding the CTRL key on PC and Cmd key on Mac).
Note: When you select an image, also select the most appropriate size for it in the Media Library's right sidebar, under ATTACHMENT DISPLAY SETTINGS . You will want to select an image size that is similar to the panel size.
After you select the images, click on the Insert into post button, and one panel for each selected image will be added in the accordion.