PictureBox memory leak

Question

Hello,

I'm trying to show a selected image from a ListView in a PictureBox.

When I select an Image from the ListView it does show up. but each time I do this the memory usage of my app shoots up and doesn't go down (I'm using rather big images)

Working code with memory issue:

        Bitmap originalImg;

        private void listView1_SelectedIndexChanged(object sender, EventArgs e)
        {
            for (int i = 0; i < listView1.Items.Count; i++)
            {
                if (listView1.Items[i].Selected == true)
                {
                    originalImg = new Bitmap(folderPath + "/" + listView1.Items[i].SubItems[0].Text);
                }
            }
           
            pictureBox1.Image = tempImg;
        }
  

I tried disposing the image before another one is loaded but I get a null pointer exception the second time an image is selected in the ListView.

        Bitmap originalImg, tempImg;
        
        private void listView1_SelectedIndexChanged(object sender, EventArgs e)
        {
            for (int i = 0; i < listView1.Items.Count; i++)
            {
                if (listView1.Items[i].Selected == true)
                {
                    tempImg = new Bitmap(folderPath + "/" + listView1.Items[i].SubItems[0].Text);
                }
            }
            
            originalImg = (Bitmap)tempImg.Clone();
            tempImg.Dispose();
            OriginalPictureBox.Image = originalImg;
        }
    }

What am I overlooking?

Thanks in advance :)