Would you be upset at this?

My partner split from his wife of 13 years last April and they eventually called it quits after therapy failed last July. We met a few weeks on, connected immediately and things have been blissful ever since.
Today however I was a bit concerned that he posted a photo of a day trip he had with his ex four years ago. It was to celebrate a big event but it seemed strange he would do that. He also put 'We had to travel ages to find food!' And again I question why he is talking about his ex when he hates her. Am I over reacting?

She wasn't in the photo but it still hurt.