You can't without a lot of effort and then at best hit or miss. Presently Vegas doesn't have anything but simple masking ability. To track several irregularly shaped objects over multiple tracks especially if they are moving is difficult. For simple shapes cookie cutter. Changing color of one or more objects is simple enough with color corrector secondary, but to have mostly black and white with a object or two in color isn't easy. For a still image embedded in your video, yes. Just drop the image on the timeline making a transparency in Photoshop or some such similar application. Is their an easier way? Soon, with Boris Red. It uses layers and you can draw on them making your own custom masks. Downside... its an expensive plug-in.