To save time when replacing multiple images in a grid, you can bulk replace all of the images in just one easy upload.
Simply click the add images icon + from the grid menu and bulk select all of the images needed from your computer. (Make sure to count the correct number of images needed for the grid.)
You can use bulk replace with template grids or existing story grids. This video demonstrates how to use bulk replace when selecting a grid from templates.
Note: when working with a template, uploading images will replace the images in the template. When uploading more images than used in the template, they will start appending at the bottom of the template.