The "shutter icon" refers to a small picture or symbol that represents a camera's shutter button. It is often used in software or apps to indicate the option to take a photo or capture an image. Full definition
The feature places a circular shutter icon next to the name of the account that took a screenshot or screen recording of your content. (androidauthority.com)
Decompiling the code revealed a file for a portrait shutter icon alongside existing camera modes like live and reverse, according to TechCrunch. (digitaltrends.com)
That means nametags would work just like Snapchat's QRs, and the shutter image above is likely going to be a Stories camera option like Boomerang or Super Zoom, which all have their own shutter icons.] (techcrunch.com)