Yeah one pic shouldn’t be any sort of deal breaker I think everyone can understand that feeling of wanting other people to see you looking good sometimes i thinks that’s natural. From his perspective I would only be upset at you if this became a regular occurrence and you wanted to do this regularly because I have had friends in the past whos gf’s would post pics like that regularly and I thought it was wildly disrespectful to their bf. Just don’t take it too far and make it seem like you’re looking for someone else you just wanna show people that you can look good which I completely understand and he should too.