In this series, Instagram Icon, Entrepreneur speaks with the individuals behind popular Instagram accounts to find out the secrets of their success.

When husband-and-wife duo Ahmed El Shourbagy and Ashley Paguyo El Shourbagy met in July 2011, Ahmed had been posting photos to his new Instagram account, @dogsofinstagram, for a week and a half. Ahmed worked in finance and didn’t have a background in marketing when he started the account, which to this day remains dedicated to posting user-generated photos of dogs. But the day he met Ashley, he hit 1,000 followers. And in Instagram’s early days, having 1,000 followers on the platform was extremely rare.

“At the time, I was working in communications and PR for a startup, studying the mobile social media habits of millennials,” says Ashley, who had invited Ahmed to a focus group. “This guy just like, waltzes in, and I find out he has this passion project.”

Ahmed had an interest in social media and an itch to do something entrepreneurial. When he posted a photo of his Boston terrier, Lucy, to Instagram, he noticed that it got a lot more likes and comments than some of his other early photos. This aligned with his observation that many of the most popular photos on the platform at any given time were photos of dogs.

“I found myself following all these strangers because I liked their dogs,” Ahmed recalls. “So here I am, following ‘Mike’ just to see a picture of his dog every once in a while, and I thought, ‘Well, this is kind of getting out of hand. I wish I could just follow one account for a daily dose of dogs, being a dog lover myself.’ And that’s kind of when it hit me.”

Ahmed and Ashley began dating, working on the project together and bonding over it. One of their first dates was a brainstorming session for the account. “We didn’t have hopes or aspirations of it becoming our full-time job or monetization, but we knew that we were onto something,” Ashley says. “It was really fun, in the very early days, to sit down and say, ‘Where do we want to see this grow? What are our goals and our objectives? What are some of the values that @dogsofinstagram stands by?’”

Two years in, they started to get approached by advertisers and sponsors and people who wanted to partner with @dogsofinstagram and do campaigns. And now, more than six years in, @dogsofinstagram has 4 million followers. The couple is also behind the account @dogsofshelters, and they partner with animal rescue organizations. Plus, they’ve spun off a ecommerce business that sells dog products, named Lucy & Co. after their terrier, and they’ve produced a book and a daily calendar using photos from their account.

@Dogsofinstagram is powered by followers submitting content. When Ahmed created the account, he was just posting generic dog pictures to the account to get it started, but from the outset, he specified an email address in the bio where people could submit their photos. He received his first submission when he had only 70 followers. Today, the Twin-Cities-based couple receives between 100 to 300 submissions per day.

This interview has been edited for length and clarity.

1. How did you get your start with Instagram?
Ahmed: At first I was like, it’d be really cool to have an Instagram page dedicated to dogs, and maybe with like a local spin, so I created Dogs of Minnesota first. For about 24 hours, that existed. And then I was like, “Wait a second. I shouldn’t limit myself here.” So, I started brainstorming how to make it bigger, and I came up with the phrase, “Dogs of Instagram.” I was playing around with “Dogs of the World.” I wanted a name that spelled out what the account was, because I thought that would be really important for growth. When people see the account, they quickly realize what it is and are more keen to follow along. I started @dogsofinstagram like, the next day, and I never looked back from there. It took off pretty much right off the bat.

2. What other platforms do you use and what percentage of the time do you spend on them vs. Instagram?
Ahmed: We do have a Facebook page. We do have a Twitter account. They’re practically inactive. Another platform just never really made sense. It’s so photo heavy, so visual, so perfect that, right or wrong, we just didn’t bother to spend time nurturing the other platforms.

Ashley: And it’s the perfect platform to showcase the beauty of dogs and the dog-human relationship. That comes through really clearly in photography, and with the introduction of Instagram video and stuff like that, it just breathes life into these pictures.

3. How much of your time do you devote to Instagram?
Ahmed: One thing we did three years ago was, we parlayed @dogsofinstagram into another project, called Lucy & Co. It’s our ecommerce boutique, a dog apparel and accessories brand. We launched in August 2014, and I think we had about a million @dogsofinstagram followers when we started. It gave us the final kick to quit our day jobs and do @dogsofinstagram and Lucy & Co. full time. We were building our website for Lucy & Co., working on our initial products for launch, doing some photography while we had our full-time jobs, while we were doing @dogsofinstagram.

4. How do you promote your account? What’s your number-one way to gain followers?
Ahmed: Same way we’ve always done it: Just put good content out there. We don’t really promote it at all. We never have. I mean, it’s Instagram’s algorithm. When you have a post that goes viral on Instagram, people who don’t follow you discover it.

Ashley: We really stand by the quality of our work and we try and curate stuff that is delightful for followers and hopefully it’s stuff that they want to share. So it’s not uncommon to go through our comments and see that people are tagging their friend during finals week, like, here’s a cute dog picture to get you through your test.

Ahmed: When we’re looking through all of those hundreds of submissions, the first thing we look at is photo quality. Is the photo blurry, or is it sharp? Are the colors right? From there we’re looking for something unique and interesting and something that will resonate with our audience. That part is a little bit less tangible. I kind of categorize it in my mind, photos are either super beautiful, like an Australian Shepherd on a mountain with a sunset behind him. Then there’s cute, like a French bulldog puppy in someone’s palm. And then there’s funny.

Ashley: And I’d also argue there’s “the everyday,” like a really cute dog snuggled up in its bed with a blanket over it because it doesn’t want to get out of bed on Monday. That’s a relatable thing. We also look for variation in dog. We’re not Chihuahuas of Instagram.

5. How do you engage with others on the platform?
Ahmed: The lowest-hanging fruit is just engaging with our followers through the comments on photos. It’s hard to keep up with that, just because we get anywhere between 100 to 5,000 comments on a photo. But we also take somewhat of a proactive approach with the community of…