In 2017, amidst the challenge of affording their $2,800-per-month rent in New York, Tessa Barton and Cole Herrmann turned their creative and technical talents towards developing photo filters for Adobe Lightroom. This endeavor laid the groundwork for Tezza, a photo-editing app named after Barton’s college nickname. Initially a side hustle, Tezza has since morphed into a lifestyle brand, amassing $26.5 million in sales last year, or an average of $2.2 million per month, as per documents reviewed by CNBC. “We started this without the intention of it becoming a business,” Herrmann shared, highlig…