The photo shows Amy Pennza standing alongside her mother-in-law, who just so happened to show up in a dress similar to hers.
RELATED: Bride angry after guest loads 10 Tupperware containers with food from wedding
Pennza says that she never thought to ask what her mother-in-law was wearing, so she was unaware of the dress until she arrived.
The mother-in-law says she did not do it to be rude, or embarrassing. However, she found a good deal and didn't want to spend a lot of money.
Hours after Pennza posted the dress photo, she shared more about the story in a series of tweets to describe her mother-in-law.
So, a couple people have asked for the story behind The Dress. Sorry for the delay! I have four kids (yes, I married him) on summer break, so my permanent state of being is "frazzled." I called my daughter "mom" the other day.— Amy Pennza (@AmyPennza) June 20, 2019
"Here's the thing: My mother-in-law is extremely frugal. And I don't mean she just enjoys a good bargain. To understand her, you have to know where she comes from. She grew up in extreme poverty. As a child, she used to sneak into the kitchen and eat match heads. That's a pica craving, and kids do it when they're malnourished. When you grow up with nothing, it stays with you. Forever, I think. No matter how much money you earn, there's always that little fear in the back of your mind that someone might take it all away. But her upbringing didn't make her hard. Or cruel. Or selfish. However, she's a bargain hunter to the bone. Her money saving strategies are legend-and often hilarious," she tweeted.
"So, yeah, the wedding dress was a shock. But it gave me a pretty funny memory. No one who attended has ever forgotten it. And, you have to admit, weddings can be forgettable. Sure, she wore a wedding dress to my wedding. But she has more than made up for it since. When I told her about this getting a lot of attention, and said I worried it might hurt her feelings, she waved it off."
SEE ALSO: Florida man arrested after crashing beach wedding during first dance