The new app is called Hobbi and was released in Colombia, Belgium, Spain and the Ukraine, according to The Information, which was the first to spot the new Facebook product.
"Organize your photos into visual collections and see the progress you're making over time," reads the app's description.
Though Hobbi has thus far had a limited release, its features would make it a direct competitor to Pinterest, which is a social media network to sharing photos and other material organized by topic.
Hobbi was developed by Facebook's New Product Experimentation team, a unit launched by the company in July to develop consumer-focused apps.
In a statement to CNBC, a spokesperson for Pinterest said the company remains "focused on building a visual discovery engine."
"Upon first look, Hobbi appears to be a photo saving app that lacks the discoverability, search, and recommendations of Pinterest. As described in the App Store, it's meant to help you document and remember the things you do, which is about the past, while Pinterest is about discovering ideas and inspiring action for the future," the spokesperson said.
Pinterest shares have bounced back from their after-hours lows, but were still about 3% below their closing price.