First image on left in grid extended layout

@media screen and (min-width: 981px) {
   .et_pb_post_extra.el_dbe_grid_extended .post-media {
      order: 2;
   }
  .et_pb_post_extra.el_dbe_grid_extended:nth-child(odd) .post-media {
      order: 0 !important;
  }
}

Add the above code snippet to your Divi Theme Options custom CSS area.

Output:

• If you want to apply this only to one page (and not sitewide), add the code to the page instead of Divi Theme Options. This is how you can add CSS to only a specific page in Divi theme.