New Post: How set webcam resolution?

I had seen this section and I also tried:

         _twain.ShowUI = False
         _twain.Capabilities.XResolution.Set (640)
         _twain.Capabilities.YResolution.Set (480)
         Me._twain.Acquire ()

Unfortunately out a mistake in Russian even though I set another language: so I thought that this resolution was only concerning dpi and not the image size.