An image with a transparent background is like a painting on a window: you can see all sorts of exciting things behind it, but you can’t reach through to touch them. αlphaPun.ch changes that!
αlphaPun.ch will trace the opaque part of your PNG or GIF image. It will then punch through the alpha channel (i.e. the transparent bit), so you can click on things behind it.
αlphaPun.ch creates a mask for the opaque part of your pic, along with masks for the clickable content behind it. These masks are placed above the actual image. Clicking a link’s mask will trigger a click on that link.