(C#) How to enlarge a PNG

Question

Image of what the game looks like currently

I'm working on a memory card matching game on visual studio code but the cards are too small the dimensions of the actual card pngs are 2048x2048 96dpi 32bit

---

private void LoadPictures()
{
    int leftPos = 20;
    int topPos = 70;
    int rows = 0;

    for (int i = 0; i < 20; i++)
    {
        PictureBox newPic = new PictureBox();
        newPic.Height = 70;
        newPic.Width = 50;
        newPic.BackColor = Color.White;
        newPic.SizeMode = PictureBoxSizeMode.Zoom;instead
        //newPic.SizeMode = PictureBoxSizeMode.StretchImage;
        newPic.Click += NewPic_Click;
        pictures.Add(newPic);

        if (rows < 5)
        {
            rows++;
            newPic.Left = leftPos;
            newPic.Top = topPos;
            this.Controls.Add(newPic);
            leftPos = leftPos + 95;

        }
        
        if (rows == 5)
        {
            leftPos = 20;
            topPos += 80;
            rows = 0;
        }

I've tried newPic.SizeMode = PictureBoxSizeMode.Zoom; instead of newPic.SizeMode = PictureBoxSizeMode.StretchImage; which does make it better BUT its still not big enough. I would like to make the png equal to the size of the picturebox don't know how to go about it :")