png to bmp in C#

Image Dummy = Image.FromFile("image.png");
Dummy.Save("image.bmp", ImageFormat.Bmp);

Certainly. You'd want to load up a Bitmap object with your png:

Bitmap myBitmap = new Bitmap("mypng.png");

Then save it:

myBitmap.Save("mybmp.bmp", System.Drawing.Imaging.ImageFormat.Bmp);