What does his chuckle/laugh mean?

I changed outfits from my uniform to my regular clothes for a party, and when my crush saw me (I didn't look at him because I was in a hurry), he chuckled. I'm sure there wasn't anything wrong with my outfit (not slutty/mismatched/outlandish/etc), so I'm just wondering what the little laugh was for? Do guys normally do this when they see someone change outfits?
What does his chuckle/laugh mean?
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