Is there a way for me to add an avatar picture to my lock screen which fits in with the background image that I have set by LogonStudio?

By this I mean having an avatar which completes the background picture. For example my background picture is of two wolves but part of one of the wolve's faces is covered by my old avatar and I'd like to get that part of the image to set as my avatar so it looks as if the background image is complete.

Does anyone know how I can do this?

Thanks

Idznak