Plugin for Shadows?

Drop shadows can do that, just not off the main image. What you have to do is take your main image, preferably cut out and freestanding, and place it at the top of a layer stack. Make your background white, then add another layer in underneath your main image. Then, take a white brush (so it doesn't show up against the background), and draw the shape out you want to cast a drop shadow from. For a shadow like that, you'll see something with tapered edges (look up how to do that with the pen tool on Google). All you have to do from there is adjust your shadow to taste by playing with the settings.



...it's kinda funny that this is almost exactly the same solution as that other guy I tried helping out in PS a little while back.

just paint it in with a soft brush or use the elipse select tool, fill it with shadow colour pixels then blur it or feather the selection before filling it. Personally i'd go with the elipse tool, fill, blur for more previewed results.