Vanishing message app Snapchat on Wednesday began giving users the option of storing images as "Memories" they can look back on or share anew.

Snapchat described the new feature as a personal collection of favorite moments kept safe below the smartphone camera screen.

"You can use Memories to create new Stories from Snaps you've taken, or even combine different Stories into a longer narrative," the California-based company said in a blog post.

"We’ll be rolling out Memories selectively over the next month or so — it's a big change for our service so we want to make sure everything is running smoothly."

Snapchat became a hit with messages that disappear shortly after being viewed.

The new Memories feature will let people only save images, referred to as Snaps, that they send.

Snapchat also added a "My Eyes Only" tag for selected saved snaps to avoid accidentally showing friends pictures not meant to be seen by others, according to the startup.

The move brings Snapchat closer to competing with mainstream messaging or photo services such as those run by Facebook or Google, which have long let people look back on images captured in the past.

The number of people using Snapchat in the United States will leap more than 27 percent this year to 58.6 million, meaning that nearly one in five people in the country will be using the service, according to an eMarketer forecast.

By the year 2020, the ranks of US Snapchat users were expected to swell to 85.5 million, according to the report.

However, eMarketer forecast that Facebook Messenger smartphone communication application would remain in the lead in this segment with its US user base growing from 105.2 million this year to 139.2 million in the year 2020.

Snapchat estimates it has more than 100 million users globally of the service for sending videos, images and text messages which vanish after being viewed. Some reports say it generates 10 billion video views per day.

Along with its playful, ephemeral style, Snapchat has tapped into an interest, particularly among young Internet users, in communicating intimately with one or a few people instead of broadcasting messages across networks.

The messaging service has been working with media partners and advertisers to reach its youthful audience.