Saving bmp image multiple times on the same path C# - c#-2.0

Question

So, I'm working on my paint application. Every time I make changes, the current screen state is copied and saved as a bitmap image on my disk (so I can use it in my paint event).
The problem occurs when I minimize and return the window to its normal state and then try to draw. This triggers my event reacting to changes, the program tries to save the image ---->>> kabooom.
It says "A generic error occurred in GDI+".. So, I've been surfing through various forums in search for the answer but none of them gave me true answer, they all mention wrong paths etc. but I'm pretty sure that's not the problem. Do I have to dispose bitmap or do something with the stream?
int width = pictureBox1.Size.Width;
int height = pictureBox1.Size.Height;
Point labelOrigin = new Point(0, 0); // this is referencing the control
Point screenOrigin = pictureBox1.PointToScreen(labelOrigin);
int x = screenOrigin.X;
int y = screenOrigin.Y;
Rectangle bounds = this.Bounds;
using (Bitmap bitmap = new Bitmap(width, height))
{
using (Graphics g = Graphics.FromImage(bitmap))
{
g.CopyFromScreen(new Point(x, y), Point.Empty, bounds.Size);
}
bitmap.Save(_brojFormi + ".bmp", System.Drawing.Imaging.ImageFormat.Bmp);
}

Answer 1

You're saving an image to disk so you can use it in another event? Wow.
Why not just use a class-global variable to store the bitmap?
class MyForm
{
Bitmap currentImage = null;
Graphics gfx = null;
private void btnLoad_Click(object sender, EventArgs e)
{
// ...
currentImage = new Bitmap(fileName);
gfx = Graphics.FromImage(currentImage);
}
private void pbEditor_Paint(object sender, PaintEventArgs e)
{
if (currentImage != null && gfx != null)
{
lock(currentImage) e.Graphics.DrawImage(currentImage, ...);
}
}
private void pbEditor_Click(object sender, MouseEventArgs e)
{
// quick example to show bitmap drawing
if (e.Button == MouseButtons.Left)
lock(currentImage) currentImage.SetPixel(e.Location.X, e.Location.Y, Colors.Black);
}
}