Draw Image with Alpha

I have images that are cached locally on the device but not yet on the server and I’d like to draw them slightly differently so the user is aware of this. I thought of using the Alpha property of the Graphics object to make the images semi-transparent but setting the Alpha property does not affect the image drawn into a Graphics object with the DrawImage method. Am I doing something wrong or is this just how it’s supposed to be? If so I’ll think of another approach, such as drawing line along the side of the image.

I’ve found a way around this - by drawing a FillRect over the image with a partial alpha. It’s not as good but it works OK.