Why would he change his display picture because of me?

Me and hin had chatted on instgram for months. He hadn’t gone out or anything.
I told him that I might have seen him recently in public wearing black beanie. I told him that I wasn’t sure if it was him or not. He then said that it was probably him.
The next day he changes his display picture to him wearing a black beanie. Before that he had his earlier pic for over a year.

Why would a guy do that?
Why would he change his display picture because of me?
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