Android :: Make Some Part Of An Image Transparent?

I have a scenario at hand, for which I need a solution as soons as possible. Here is the problem statement: I need to show an image overlapped by some other image, 100%. The condition is that the picture in background should also be visible through the foreground picture but only through some part of the foreground picture. Please try to visualise how it should look like. There is a picture shown and in middle of it, there is a transparent area through which the background image is visible. I knew that I can make an image transparent and make the background image visible but here I want only some part of the foreground image to be transparent so that it looks like sort of picture frame applied to the background puicture. And for those who read the statement carefully would have understood that the ultimate thing desired is to have a picture frame applied to the picture. Can anyone please suggest a good way to do this.