Millennials will share practically any strange GIF or meme online with their friends these days, opening up a new, weird marketing tactic for brands. For Starbucks, that means creating a William Wegman-like picture of a dog drinking iced coffee, or an image of cats and a rainbow floating above a Frappuccino.

This summer, Starbucks and agency Swift are going all-in on the mobile messaging and emoji trend to promote the coffee shop's icy Frappuccino drinks. The chain has created 21 branded GIFs it's releasing today on the mobile app Popkey that people can text to one another.

After downloading Popkey, smartphone owners need to allow the app to access their built-in keyboard in the phone's settings. From there, folks can find and send Starbucks' branded GIFs in a special section of the app that bundles all of Starbucks' images together.

While the Frappuccino name is trademarked by Starbucks, Popkey founder Adrian Salamunovic explained that the animated pictures aren't meant to look like a traditional ad. "The keyword is 'subtle' branding—it's not in your face," he said. "What fails hard in the GIF world is things like watermarks or hashtags." Salamunovic declined to say how many downloads Popkey has, but said 50 percent of its users play with the app monthly.

Adweek got the first look at the Popkey GIFs poised to take over teens' text messages today. Starbucks is also running the pictures on social media, and it built a pack of digital stickers in the Studio mobile app with similar creative.