By far the easiest way to achieve this is to drop a high-res copy of the "me doing dangerous stuff" photo into Xara Designer, draw around the bits you want to keep, Intersect shapes, and export the resulting image as a transparent PNG. I've yet to see a plugin that can crop out backgrounds more accurately than the human eye. I have Corel Knockout and Photoshop CS1 and I never use them because me and Xara Designer make a better team