Right way to dispose Image/Bitmap and PictureBox

I don’t think there is a real memory leak. The problem is that you don’t dispose the old bitmap, it is up to the GC to clean the stuff. But there is no deterministic way to say when this will happen.

So i think if you’re going to loop through a lot of pictures, you’ll see some memory increase and at some other point it will fall down or resist at one position.

I didn’t test it, but maybe this will help a little to make it more deterministic:

public void Draw() {
    Bitmap bmp = new Bitmap(240,320);
    using(var g = Graphics.FromImage(bmp))
    using(var solidBrush = SolidBrush(Color.Black))
    {
        // draw something with Graphics here.
        g.Clear(Color.Black);
        g.DrawImage(Images.CloseIcon, 16, 48);
        g.DrawImage(Images.RefreshIcon, 46, 48);
        g.FillRectangle(solidBrush, 0, 100, 240, 103);

        //Backup old image in pictureBox
        var oldImage = pictureBox.Image;
        pictureBox.Image = bmp; 
        //Release resources from old image
        if(oldImage != null)
            ((IDisposable)oldImage).Dispose();            
    }
}

Update

And another idea inspired by jack30lena:

public static Bitmap LoadBitmap(string path)
{
    //Open file in read only mode
    using (FileStream stream = new FileStream(path, FileMode.Open, FileAccess.Read))
    //Get a binary reader for the file stream
    using (BinaryReader reader = new BinaryReader(stream))
    {
        //copy the content of the file into a memory stream
        var memoryStream = new MemoryStream(reader.ReadBytes((int)stream.Length));
        //make a new Bitmap object the owner of the MemoryStream
        return new Bitmap(memoryStream);
    }
}

The idea behind my second code sample is to get rid of the file handle and copy the file content into memory. Afterwards the Bitmap will taken ownership of the MemoryStream which will be disposed within my first sample by calling the oldImage.Dispose().

By using this approach there should never be more then two images in memory, thous leading only to OutOfMemoryExceptions by really big pictures or small amount of RAM.