The move comes as social media platforms are scrambling to squeeze more revenue out of their sprawling user base. Last year, both Instagram and Pinterest - a kind of digital inspiration board - added the ability to buy products displayed in photos (Instagram called it a "Shop Now" button; Pinterest dubbed it a buyable pin).
Instagram said in a recent blog post that offering more context on products will make it easier for shoppers when they are weighing a possible purchase.
"Most mobile shopping experiences today take people from the shop window right to check out - without giving consumers the opportunity to consider a product and get more information," the company wrote.
Instagram said internal research showed that only 21 percent of consumers buy a product the first day they see it online. Most tend to spend a day or longer mulling over an item before buying.
The retailers included in this test can seed their photos with more information, available through a "tap to view" icon. When tapped, tags will pop up on one or more products in the photo, along with prices. Users can tap on a tag to get more details, and then click on the "Shop Now" button to buy it.
Timely, incisive articles delivered directly to your inbox.