Dropbox's experimental build 2.3.12, first spotted by MacStories, not only gives users a sneak peek at the forthcoming update, but also lets Dropbox test out the new features in the wild.
The first addition is a tool that automatically saves a screenshot to a user's Dropbox. In the Mac version, when users take a screenshot, it is automatically uploaded to a special folder in their Dropbox. For quick sharing, the public link to the created file is automatically copied to the OS X clipboard, which can then be pasted in any number of apps to send off to collaborators.
With the latest experimental build, Dropbox has also implemented "Move to Dropbox," a feature that ties in with contextual menus in OS X. When users command-click, or right click, on a file or folder, a new "Move to Dropbox" option will appear that links to their main Dropbox folder. The feature works with almost any file type and location in Finder.
The "Import from iPhoto" feature uses iPhoto albums to create Dropbox albums for sharing and viewing online. Macs must be running iPhoto 7.0 or higher to take advantage of the functionality.
Finally, the company promises "much faster" upload and download speeds for larger files, which should be a boon for collaborators using the service to constantly edit and sync documents remotely.
Dropbox experimental build 2.3.12 for Mac can be downloaded from the Dropbox forums, or through this direct link.