Last fall, a New York-based startup called Aviary went live, offering digital artists an online image-editing tool with features that could normally only be found in expensive software. Last month, the company released software that lets anyone integrate these tools into their website; some sites are now using the software to reinvent the way that they use images, allowing visitors to contribute cartoons for contests, modify photographs in newspapers, and even tweak the overall design of an online storefront.

The new application programming interface (API) that makes this possible has tapped the potential of collaborative image editing. Aviary’s CTO, Israel Derdik, says that the New Yorker used the company’s API to hold a cartoon design contest. Participants visited the New Yorker site and selected from a preloaded library of cartoons that they could modify and edit, turning layers on or off, to generate a unique cartoon.

The NY Daily News also used the API to let its online readers poke fun at current events: when Air Force One flew low over New York, the paper gave readers the chance to edit the image and place the plane in other images of the city’s skyscape. The online retailer Shopify is using the API to let its customers retouch images of items that they plan to sell, instead of needing to retouch using desktop software before uploading to the site.

By releasing the API, Aviary hopes to boost adoption, says Derdik. “Getting wider distribution is precisely our goal,” he says. “We think that we can continue to develop our offering and make Aviary be the Web’s editing tool for all creative mediums.”

Aviary consists of four tools: Phoenix for photo editing, Raven for graphic design, Toucan for color swatches, and Peacock for pattern generation. They were built using Flex, a platform for developing powerful Internet-based applications created by Adobe. (Ironically enough, Adobe also makes Photoshop and other desktop-based image-editing tools.) When a person tweaks a photo using Aviary, she does so using software that’s running via the Flash player in her Web browser. When she saves the file, it’s saved to Aviary’s servers, which keep a record of all changes that are made. If the servers fail due to traffic spikes, say, the files are automatically transferred to a backup: Amazon’s S3 servers.

All four Aviary tools can be accessed using the API. “This means that whether people are creating images, vectors, color palettes, or visual effects, all of the functionalities of the tool are possible to access with no log-in required,” says Derdik. So when a person navigates to a website that has integrated the tools, she doesn’t need to have an account with Aviary.

Thomas McKelvey, who runs an online store called Milksites, says that he plans to integrate Aviary tools with his site soon. “We host online stores built for nontechnical users,” he says. “Our clients need to resize, crop, and otherwise do simple touch-ups to product photos all the time. No other Web-based or desktop-based photo editor can seamlessly integrate with our software while also being easy to use.”

Creating an open API is a strategy pursued successfully by many Web companies, including Flickr, the photo-sharing site, and Twitter, the microblogging service. Both of these sites opened their APIs to outside developers, and there are now hundreds of third-party tools that plug into their platforms. “Aviary is doing a really smart thing in opening its API,” says Shawn Rider, manager of technologysolutions at PBS and an Aviary user. “They’re clearly in tune with the trends.”

“I couldn’t really see Photoshop showing up inside a small-time T-shirt design shop on the Web,” says Rider. “But at the same time, that’s the sort of thing Aviary’s API is designed for.” He suspects that Aviary will push Adobe, which already has a minimal editor on the Web, to expand its Web-based offerings. “All these companies that had previously made bulky applications that lived on the desktop will have to think of ways to take advantage of the network,” he says.

Aviary’s Derdik says that the company will release a more advanced API that includes a way to authenticate users and let them access files stored on a company’s own servers. “This is useful if someone wants to build an application that can track sources used, color information in a creation, and derivatives made,” he says.