Use embedded thumbnails in the grid view.

ui/file_manager/file_manager/foreground/js/file_grid.js

Index: ui/file_manager/file_manager/foreground/js/file_grid.js
diff --git a/ui/file_manager/file_manager/foreground/js/file_grid.js b/ui/file_manager/file_manager/foreground/js/file_grid.js
index d3ea59fc26d1df2ec6f711a01ad389d42102e5a2..1385e7d5fc4ae7eb77f63d8a049d1e9b9927c144 100644
--- a/ui/file_manager/file_manager/foreground/js/file_grid.js
+++ b/ui/file_manager/file_manager/foreground/js/file_grid.js
@@ -75,7 +75,7 @@ FileGrid.prototype.updateListItemsMetadata = function(type, props) {
                                   this.metadataCache_,
                                   this.volumeManager_,
                                   ThumbnailLoader.FillMode.FIT,
-                                  FileGrid.ThumbnailQuality.HIGH);
+                                  FileGrid.ThumbnailQuality.LOW);
   }
 };
 
@@ -121,7 +121,7 @@ FileGrid.decorateThumbnail = function(li, entry, metadataCache, volumeManager) {
                                   metadataCache,
                                   volumeManager,
                                   ThumbnailLoader.FillMode.AUTO,
-                                  FileGrid.ThumbnailQuality.HIGH);
+                                  FileGrid.ThumbnailQuality.LOW);
   }
   frame.appendChild(box);