Creating and Saving a Picture

There are 3 steps to creating and saving a picture:

1. Create a Bitmap object.
2. Edit it using Graphics object.
3. Call Bitmap.Save method to save it.

Code Example:

Bitmap bm = new Bitmap(100, 100);
Graphics g = Graphics.FromImage(bm);
g.DrawEllipse(new Pen(Color.Red), new Rectangle(5, 5, 90, 90));
bm.Save("bm.jpg", ImageFormat.Jpeg);

Here is what it looks like:
If you would like to edit an existing image instead, you can use:

Bitmap bm = new Bitmap("existingImage.jpg");

More Info: MSDN: Bitmap Class