The head of my department sent me a photo I didn't ask for

I worked in hospital administration. I loved my job. I was good at it. I had just been promoted to a coordinator role and was genuinely excited about the work. The head of my department was respected across the hospital. He'd been there for twenty years. Everyone knew him. He started texting me about work things. Then personal things. I kept replies short and professional. Then one night he sent me a photo. I won't describe it. I think you know what kind of photo it was. I showed it to a trusted colleague who told me to go to HR immediately. I did. I walked in the next morning with my phone. The HR representative — a woman — looked at the photo, looked at me, and said: "Are you sure you want to do this? He's been here a very long time." I reported it anyway. The investigation took four months. During those four months I had to continue working in the same building, attending the same meetings. He acted like nothing had happened. Other colleagues noticed I had gone quiet and assumed I was struggling with the new role. He retired at the end of the investigation. Full pension. A farewell party with a cake. I transferred to a different hospital.