in Photoshop, go to the help menu, select "export transparent background wizard", follow the few easy steps. & you will have an .eps file that you can place over yellow or anything else.
What the "wizard" does is just to create a vector path & then create a mask with it like Fred suggested. It is often a rather crude "path", so, you may need to work harder making a better path, but it is very handy for designing when you want to see the results, or get client approval before working harder.