It's one of those moments that many moms of two or more kids knows, but can't be explained until you've actually been through it.

It's when your first baby is longer your only baby.

You know, of course, that you will love your second child just as much as you love your first. But there's a sort-of sadness at saying goodbye to the days when it was just you and your little one.

That experience is the reason photos of a mom introducing her toddler son to his new baby sister have been shared more than 50,000 times. The mom in the photos, Ashley Clarke, told "Good Morning America," "I think the picture, along with Jordan's [the photographer] words, perfectly captures the crazy mix of emotions a mom has about adding a new baby to the mix. Being excited for the new baby but also mourning what once was. And praying your first little love doesn't hate you forever for ruining the status quo."

PHOTO: Ashley Clarke is pictured here with her son and daughter.
Jordan Burch Photography
Ashley Clarke is pictured here with her son and daughter.

Jordan Burch, the photographer who captured the images, told "GMA" she was initially "taken aback" when she realized how nervous Ashley was for Jackson [her 21-month-old son] to see her with a new baby.

"She was anxious from the minute I got there and when he came in and broke down, I knew it confirmed all her fears. But I also knew -- as a mom of four -- that's they'd all recover quickly."

Clarke explained to "GMA" much of her nervousness came from Jackson being a preemie.

"I struggled emotionally for at least a year as I kind of came to terms with everything," she said. "He's always been the little light that came from all the craziness. And I was so afraid to have Emma [her daughter] when he was only 21 months old. I felt like I was betraying him," she said.

Though Jackson's initial reaction was what his mom feared, the family did indeed recover quickly, as Burch predicted.

She went to a follow up session at the family's home shortly after the initial photos and Jackson gave his sister a hug.

"Now I can't imagine it any other way and I'm so glad they are close in age," Clarke told "GMA." "He's very good with her and she lights up when she sees him. Although he always tells me, 'No more babies. Only Emma.'"