AITA for ruining my sister's wedding?

I have a younger sister(33F). I (43M) am married with 2 teenage daughters (16 and 14). My sister is married to "Kevin" and they have a boy (5) and a girl (3). Kevin is a great guy. He's a very nice person and is very good to my sister and their children. He treated my niece and nephew incredibly well at the wedding.<br><br>Our family is quite well off due to a number of successful business endeavors that my father and I have been involved in. My sister and her family are wealthy as a result. They are not rich, but they are quite well off. My wife and I are also quite well off, but not to the extent that my sister's family is, as my wife and I have chosen to pursue careers that, while fulfilling, are not as lucrative.<br><br>My parents have always had a habit of spoiling my sister and buying her whatever she wants. When it comes to my family, they tend to be more reserved in their gifts. My daughters understand that they are not going to get the same treatment as their cousin and they are OK with that.<br><br>For my sister's wedding, my parents spared no expense. It was at a very fancy location with several hundred people in attendance. Many of the people there were from my sister's social group - i.e. other wealthy people.<br><br>My wife and daughters unfortunately do not share the same level of wealth as my sister and her friends. They do not have the money to buy expensive clothes and they tend to shop at Target or TJ Maxx for their clothes.<br><br>At the reception, there was a photo booth. My sister and I were in the photo booth taking pictures with our kids. My sister and her kids were all dressed up in very fancy clothes and my daughters and I were dressed in clothes from Target.<br><br>My sister started to complain about how my daughters and I looked and how we were going to "ruin" her wedding photos. She said that we were "poor" and "looked like we were from trailer park". She told me that I should buy my daughters nicer clothes so that they would "fit in" with the other guests.<br><br>I was very angry at this, but I kept my cool and reminded her that since she was the bride, she shouldn't be worrying about what other people wear. She continued to complain and then I lost my temper and yelled at her. I told her that she was being incredibly selfish and self-absorbed. Other people at the wedding started to stare and the wedding kind of went off the rails from there. My sister is furious with me and my parents are angry at me as well.<br><br>AITA?<br><br>Edit: <br><br>1. We were dressed as directed by the invitations.<br><br>2. My sister and her husband paid for the wedding. My parents paid for my sister's dress, the flowers, and the photographer.<br><br>3. My daughters and I are well dressed. My wife loves to dress my daughters up and they always look very cute. They did not look sloppy or poorly dressed.<br><br>Update:<br><br>I've read a lot of the comments on this post and I want to apologize for not responding to everyone. There are a lot of comments and responding to each of them would be very time-consuming.<br><br>It's a bit complicated with regards to the photos. My sister did not want my daughters/niece/nephew in the photos. However, she did want my wife in the photos and she told us to "crop out" my daughters.<br><br>Based on some of the comments, I am beginning to wonder if there is something that I'm not seeing/remembering. It's possible that my sister's behavior was somehow a result of something that I did or said. I've sent her some texts last night asking her to go to therapy with me.<br><br>With regards to my parents, they're older and not familiar with smartphones, so they won't see this post.<br><br>I appreciate everyone's feedback.<br><br>Update 2:<br><br>I just got off the phone with my sister. We are going to go to therapy next week to work through our issues.<br><br>Also, I just wanted to clarify that when I said "target dress" earlier, I meant that my daughters' dresses were from Target. We did not buy the first thing we saw at Target. My wife spent a lot of time looking for the perfect dresses for the girls.