Check out example codes for "how to allow user import image c#". It will help you in understanding the concepts better.

Code Example 1

private void cmdBrowser_Click(object sender, EventArgs e)
        {
            OpenFileDialog fileOpen = new OpenFileDialog();
            fileOpen.Title = "Open Image file";
            fileOpen.Filter = "JPG Files (*.jpg)| *.jpg";

            if (fileOpen.ShowDialog() == DialogResult.OK)
            {
                picImage.Image = Image.FromFile(fileOpen.FileName);
            }
            fileOpen.Dispose();
        }

Learn ReactJs, React Native from akashmittal.com