first we should open new windows application project
then we have to add a PictureBox , a button , OpenFileDialog.

Button1:
name = btnopen
text = open image

Button2:
name : Exit
Text : Exit


PictureBox:
name = imgloader
Size Mode : Streach


OpenFileDialog:
name : open
Filter : (you can add any format but dont forget it should be Pictures formats)

double click in the button1 and write the Code

 private void btnopen_Click(object sender, EventArgs e)
        {
            if (openFileDialog1.ShowDialog() != DialogResult.Cancel)
            {
                imgloader.Image = Image.FromFile(openFileDialog1.FileName);
            }
        }

then double click to button2 and write:
 this.Close();

Finish

just open the project and test it