Katie Driscoll calls it a campaign – but others might call it a crusade.

Either way, for the past two years she has been on a vigorous mission to help cast children and adults with intellectual disabilities or physical differences in advertisements ranging from local to international.

"We're a society that's all about inclusion for children," Driscoll, 40, of Palos Park, Illinois, tells PEOPLE. "But when you look at imagery, you almost never see children with disabilities of any kind."

In 2012, she and her friend, Steve English, created a website, Changing the Face of Beauty, to promote the use of special-needs models in mainstream ads.

The response has been astonishing.

They have helped at least 20 models from all over the world land gigs – and those are just the ones they know about.

"I tell companies and designers: 'When you're putting your advertising out there for all to see, why wouldn't you include someone with a disability?' " says Driscoll.

Holly Ramsburg is one grateful parent.

"What Katie is doing with her campaign is life-changing for a lot of us," says Ramsburg, 44, of Naperville, Illinois, whose 8-year-old daughter has Down Syndrome and has been in several ads promoted by Driscoll's campaign.

It all started with Driscoll's youngest child, four-year-old Grace, who has Down Syndrome. After having five boys, Driscoll was delighted to finally have a reason to buy girls' clothing and started posting photos of Grace wearing every new outfit on her blog.

She then reached out to small online vendors to see if they might be interested in using Grace to model their products to show people that "Grace is more than just her diagnosis."

After forming the website, Driscoll began sending pictures of Grace and other special-needs kids she'd photographed to various companies, urging them to consider using special-needs models in their mainstream ads.

As word of her campaign spread through social media, she was inundated with photos of special-needs individuals – including individuals with Down Syndrome, cerebral palsy, dwarfism, autism, reliance on devices such as wheelchairs, etc. – sent by parents or guardians from all over the world.

Most of those images were transferred from the campaign's website to its Facebook page for public viewing, where company reps can view the portfolio and contact Driscoll or English if they're interested in using any of the models. Driscoll then puts the company reps in touch with the families.

"There's more than $200 billion in discretionary spending from individuals with disabilities, so why wouldn't they be represented?' " says Driscoll, who also runs a small, separate commercial photography business out of her home.

She also champions inclusion.

"Often, when I talk to advertisers, they say: 'Great idea! We'd love to do a campaign celebrating special-needs children!' " she says. "And I say, 'No, I'm talking about including, say, one child who has a difference, along with everyone else in the ad.' "

Driscoll is grateful for responses from agencies like Chicago-based Real Talent Inc., which specializes in representing "real people" as models. Last year, agency founder Markus Giolas signed 18 models from the CTFOB database.

"I wish there were more people at high levels demanding 'real' models like the ones Katie is promoting," Giolas says, "because the more people see those models in mainstream advertising, the more they'll become comfortable with it."

Driscoll's campaign has benefitted from some celebrity support, including Maria Shriver. The Kennedy family member championed the effort on her blog.

But for Driscoll, the most important feedback is from the parents themselves – like one mother whose 23-year-old daughter is profoundly disabled and non-verbal.

"She told me, 'Thank you for changing my perception of my daughter,' " says Driscoll.

The mother also told Driscoll: " 'I've gone through life viewing my daughter as a disabled child,' and now I see her as a beautiful young woman – and I see opportunity for her.' "