Why is the Win Forms square drawn incorrectly?

Question

C++ / C#

Good afternoon. In general, I do Paint on win forms. I made pencil drawing and rectangles, but when I add an image to the picturebox and move it or stretch it, the rectangle is drawn on correctly.
Here is my code:

void pictureBox1_MouseDown(object sender, MouseEventArgs e)
{
    isLMBclicked = true;

    if (mode == "rectangle")
    {
        point1 = new Point(e.X, e.Y);
        rec.Location = e.Location;
        newRectangle.FlatStyle = FlatStyle.Flat;
        newRectangle.FlatAppearance.BorderColor = pen.Color;
        newRectangle.FlatAppearance.BorderSize = trackBar1.Value;
    }
}

void pictureBox1_MouseUp(object sender, MouseEventArgs e)
{
    isLMBclicked = false;
    if (mode == "pen")
    {
        arrayPoints.resetPoint();
    }
    else if (mode == "rectangle")
    {
        graphics.DrawRectangle(pen, rec);
        pictureBox1.Image = map;
        rec = new Rectangle();

        newRectangle.Visible = false;
    }
}

void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
    if (!isLMBclicked) { return; }

    if (mode == "pen")
    {
        arrayPoints.setPoint(e.X, e.Y);

        if (arrayPoints.GetCountPoint() >= 2)
        {
            graphics.DrawLines(pen, arrayPoints.GetPoints());
            pictureBox1.Image = map;
            arrayPoints.setPoint(e.X, e.Y);
        }
    }
    else if (mode == "rectangle")
    {
        point2 = new Point(e.X, e.Y);
        if (point2.X > rec.Location.X && point2.Y > rec.Location.Y)
        {
            newRectangle.Visible = true;
            //newRectangle.BackColor = pen.Color;
            var newSize = new Size(point2.X - rec.Location.X, point2.Y - rec.Location.Y);

            if (MouseButtons == MouseButtons.Left)
                if (newSize.Width > 5 && newSize.Height > 5)
                {
                    rec.Size = newSize;

                    newRectangle.Location = new Point(point1.X, point1.Y);
                    newRectangle.Size = newSize;
                    Invalidate();
                }
        }
    }
}

So it is necessary:


​​And it turns out like this:


That is, the cursor is in one place, and the square is in another, but when I release the LMB, it gets to the right place