I Managed to compile the downloaded example, which didn't work earlier.
Now Visual Studio is saying:
'Glu' is obsolete: 'Use OpenTK math functions instead.'
OpenTK.Graphics.Glu.Build2DMipmap(OpenTK.Graphics.TextureTarget.Texture2D, (int)PixelInternalFormat.Rgba, (int)image.Size.X, (int)image.Size.Y, OpenTK.Graphics.PixelFormat.Rgba, OpenTK.Graphics.PixelType.UnsignedByte, image.Pixels);
what exactly does that mean? An equivalent doesn't seem to be present in that context, so how do I do what would have been done with the 'Glu' context?