No, absolutely not, I've spoken to him about this for 6 months, explaining, letting him know how I felt, etc etc etc, for 6 months (!) - her pic was the last straw. Generally I do tend to bottle things up - but in her case, he knew how I felt about what was going on, and he knew that I had cut off with her 3 months prior because I felt disrespected by her actions. Anymore talking about this to him and I would've driven myself up the walls!
You are right, I should have been pissed at him, but I was pissed at her too due to the lingerie shopping trip (I'm sure he wasn't the one buying - it was her buying for her bf), the lying to my face (at least he didn't lie to me when he went to see her), and the disrespect (she was like a sister to me, and I never expected this from her). He passively encouraged her to continue disrespecting me and she actively did the same too (asking him to drive her places, run her errands, etc).
You can not defend her - she lied to my face and disrespected our friendship. Yet, in all fairness they were both as bad as each other. Hence, they have both been trimmed.