C# draws my image too large and regardless of mouse position

I'm currently working on a battleships game,but i've ran into an issue.So far i've managed to draw the grid.the purpose of the draw method is to draw an image(don't know how to/if i can color a certain surface) inside a square in the grid,when i left-click. the problem here is that,even if the image's size is 25x25(the size of a square) it occupies like half the screen,and that's when it works.50% of the times when i run nothing happens,and the other 50% it draws a huge image in the middle of the screen,regardless of where the cursor is located or if i left-click.

public partial class Form1 : Form
{

    public Form1()
    {
        InitializeComponent();
        this.Paint += new PaintEventHandler(form1_paint);
    }
    private void form1_paint(object sender, PaintEventArgs e)
    {
        draw(e);
    }
    int x,y;
    private void draw(PaintEventArgs e)
    {

        if (MouseButtons.Left != 0)
        {
            x = Cursor.Position.X;
            y = Cursor.Position.Y;
            Image poza = Image.FromFile("D://C//12E//c#//yellow4.jpg");
            if (x < 301 && x > 24 && y < 301 && y > 24)
            {
                PointF coltz = new PointF(x / 25 * 25, y / 25 * 25);
                e.Graphics.DrawImage(poza, coltz);
            }
        }

    }

Does anyone know how i can solve this?or if someone has a better idea for a battleships grid, I am open to suggestions.Thanks!