Whoever is doing this has either really got it in for activists or has mental health problems. Ordinary people have had their photos used as part of vendettas against other people & to set up all sorts of fake groups, fundraising ventures etc. What this person is doing is very much against the law & if your photo has been used to irritate, harrass or abuse someone else without your knowledge this is very frightening and dangerous.
There is also the chance that this person could use other people's pics to make contact with others under false pretences for sexual reasons for example.
Everyone should have a look through their FB / myspace friends lists to check that the profiles on there are genuine & that they have joined genuine friend profiles.
Some AR groups / personal pages are full of profiles made by one person who uses what they are doing to bombard with messages, bulletins & in the case of FB fill up the freinds quota preventing genuine people from contacting you. This person is not doing this alone so it could be NETCU or a group of nasty Big Pharma consorts.

Very, very bad.