Colleague sent me a photo of him in the bath!

So I’ve only worked with this guy twice, his girlfriend also works at the same company. I helped him find a driving instructor and he had a deep conversation about his future life and fears of his future choices and what may happen to his relationship in the future because of him going into the military. So he messaged me to let me know how his first lesson went and then told me he was going to chill out, have a bath and some beers, I told him that sounds like a good plan and that he deserves some chill time. Our jobs are stressful. He knows I’m engaged and have a family. He then sends me a photo of him in the bath, I told him to enjoy just to ignore the fact I got a topless picture in the bath. I told him I’m probably going to do the same later because my tattoo has finally healed and I can now have a bath. He asks how it’s looking so I show him a photo of it healed as I showed him and other colleagues a photo of when it was freshly done as it’s a memorial tattoo from when my dad passed away last month. He then said I should take the photo at a different angle with a ;) and went on to say he bets I took my pants down in the kitchen. I told him nice try and he tried to say he was only joking. Was he trying to flirting with me and do I tell the girlfriend?