MiG-21 visual ID question.

Is there any easy visual indications between the MiG-21M, MiG-21MF and MiG-21bis?

I’m attempting to ID photos of Warsaw Pact MiG-21s and attempting to work who missile models and marks.

For example:
http://img.photobucket.com/albums/v358/Hugr1/MiG-219483.jpg

As an aside is this a Libyan MiG-23 with R-13M?: http://sistemadearmas.sites.uol.com.br/aam/atoll1.jpg