thumbnails now lazy load. when it is loading, a content loading gradient is shown in front of it

made file cards look better on mobile devices

src/app/file-card/file-card.component.ts

@@ -20,6 +20,7 @@ export class FileCardComponent implements OnInit {
   @Input() isPlaylist = false;
   @Input() count = null;
   type;
+  image_loaded = false;
 
   constructor(private postsService: PostsService, public snackBar: MatSnackBar, public mainComponent: MainComponent) { }
 
@@ -43,6 +44,10 @@ export class FileCardComponent implements OnInit {
 
   }
 
+  imageLoaded(loaded) {
+    this.image_loaded = true;
+  }
+
   public openSnackBar(message: string, action: string) {
     this.snackBar.open(message, action, {
       duration: 2000,