Flutter Listview freezes while it is loading thumbnail images from video url and my app crashed

i am try to get image from video url when my list scroll but when i use of video thumbnail library and call it in my app list freezed and my app crashed this is my code

  Future _loadMore(context) async {
final diractory=Provider.of<DiractoryPath>(context,listen: false);
Provider.of<LoadState>(context).setLoadState(true);
final index= Provider.of<IndexLazyloading>(context);

if(moves.length!=index.oldmove){
  resetlist(context);
}
// Add in an artificial delay

for (var i = index.currentindex; i <= index.currentindex + increment && i<moves.length; i++) {
  File f=new File( "${diractory.diractory}/${moves[i].videourl.split("/").last.replaceAll("mp4", "png")}");
 if(!f.existsSync())
await getimage("${strings.baseurl}/videos/${moves[i].videourl}",context);
  index.setdata(i);
}
await new Future.delayed(const Duration(seconds: 2));
Provider.of<LoadState>(context).setLoadState(false);
index.setcurrentIndex(index.data.length)  ;
index.setoldMove(moves.length);
}

and this is my plugin that used

Future<Null> getimage(videourl,context)async{
 final uint8list = await VideoThumbnail.thumbnailFile(
 video: videourl,
thumbnailPath: Provider.of<DiractoryPath>(context).diractory,
imageFormat: ImageFormat.WEBP,
maxHeightOrWidth: 0, // the original resolution of the video
quality: 75,
 );
}

i try with png but dont work this is my list that call this function what is problem in this code please help me

 LazyLoadScrollView(
    isLoading: loadstate.isload,
    onEndOfPage: () => _loadMore(context),
child: ListView.builder(
itemCount: indexlayze.data.length,
itemBuilder: (context, position) {
return _buildProductItem(context,position);
},
));

my list get 10 image thumbnail when reach to end of list but is very slow how to handle it