There are 2 available modules in the Divi Gallery Extended plugin.
Use this module for uploading and sorting images manually to your Gallery.
To add more images or delete some, edit the module again and add or delete the images you want.
Dynamic Masonry Gallery
Use this module if you don’t want to upload images manually and feed them to the gallery by their category.
In this case, images saved to the media library need to have categories assigned to them.
In this case, you won’t have to edit the page again when you want to add more images to your gallery. Instead, you upload the image to media library, then click on an image there and select the category you want to associate that image to. And it will automatically populate the image on the front-end.