Dropbox released Carousel, the file-hosting service's new app for organizing and and sharing photos and videos, at an event in San Francisco Wednesday.

The app enables users to view and organize all of their images that have been shared or backed up using Dropbox — without having to store them locally on their device.

One of Carousel's most useful features appears before you even sign in: the ability to automatically back up your device's camera roll. Once enabled, all the photos you take will automatically be synced to Dropbox when connected to Wi-Fi (syncing over Wi-Fi is the default setting, but users can also choose to sync over a data connection).

Photos are grouped chronologically by event, with the most recent appearing first. At the bottom of the app is a scrollable timeline that lets you jump between years or months.

Image: Carousel

Overall, the app is surprisingly responsive. Using the slider, navigating between hundreds of images that span years only takes as long as it takes to swipe across the bottom of your screen. Images load almost instantly with no noticeable lag — even without a Wi-Fi connection.

Obviously, the app relies on Dropbox's ecosystem, so if you haven't backed up or shared many photos to Dropbox, the app won't show much beyond what's on your camera roll.

Dropbox has also built a platform for private messaging into the app. Users can share any photo, or a group of photos, with friends via email or text message. If photos are shared with people who do not have the Carousel app installed, they can view a preview of the image, but will need to download the app in order to save it or respond.

Image: Carousel

Dropbox is billing Carousel as a way to store memories; this sentiment seems almost cheesy at first, but if you have years of images on Dropbox, the app may surprise you.

When I first logged on, I was pleasantly surprised to discover that Carousel resurfaced a series of photos — now almost 10 years old — that I thought only existed on an old external drive. As it turns out, the images had been sitting in my Dropbox account for more than two years, but had gotten lost among my many folders and files.

However, the app noticeably lacks several features — a search function, for example — but given that this is Carousel's first release, we'll likely see more features added in future updates.

It's also worth pointing out that by encouraging users to back up and save all their images to Dropbox, the company may be subtly pushing users toward upgrading to paid accounts.

Dropbox currently offers 2 GB of free storage under its free plan, although that amount can be increased up to 16 GB by referring friends or participating in other promotions. Even so, 16 GB will go quickly if users are storing a large number of photos in their accounts. Pro accounts start at $9.99 a month (or $99 a year) for 100 GB of storage.

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