Legal Question in Criminal Law in California

yes

Yes. There are better ways to ask a victim to identify a suspect, and there are ways to challenge the results of the method you describe. But if the victim already knows the suspect it is unlikely that their identification was unduly influenced by the photo. I would need to know more about what happened before I could say whether you have a decent argument to make. Based upon what little you have told us, my sense is that you don't.