Thumbnail icon overlay to show Admins/Memebrship Level

I have set up levels on my site.  Each level has an Icon. I would like to add the that membership icon as an overlay image on that users avatar and thumbnail. I would like to place it in the ottom right corner of the avatar and the thumbnail. Also if you are an admin on the site I would like for it to not show a membership icon but an admin Icon. All these should not affect the avatar nor thumbnail that the users have uploaded.