Batch/pause foreach loop after specified number of returns

I have a C# "foreach" loop I would like to run a batch of 100, then pause for a specified period of time. How can I go about batch processing a "foreach" loop? I have tried many examples and all have failed. Here is the code contaning the loop. Thank you very much.

foreach (string filename in filenames)              {                    PictureBox pic = new PictureBox();                      pic.ClientSize = new Size(ThumbWidth, ThumbHeight);                  pic.Image = new Bitmap(filename);                                      if ((pic.Image.Width > ThumbWidth) ||                      (pic.Image.Height > ThumbHeight))                  {                      pic.SizeMode = PictureBoxSizeMode.Zoom;                  }                  else                  {                      pic.SizeMode = PictureBoxSizeMode.CenterImage;                  }                                      pic.DoubleClick += PictureBox_DoubleClick;                                         FileInfo file_info = new FileInfo(filename);                      tipPicture.SetToolTip(pic, file_info.Name +                      "\nCreated: " + file_info.CreationTime.ToShortDateString() +                      "\n(" + pic.Image.Width + " x " + pic.Image.Height + ") " +                      ToFileSizeApi(file_info.Length));                      pic.Tag = file_info;                                                                                 pic.Parent = flpThumbnails;                                     }                

https://stackoverflow.com/questions/67342825/batch-pause-foreach-loop-after-specified-number-of-returns May 01, 2021 at 12:15PM