Sprout Studio helps you understand your business at a whole new level by using tracking technology to see whether or not your client has made a download from the gallery. This function only tracks the entire gallery download as a whole and not each individual image.
On the right-hand side of the Gallery page, when the client has logged in and completed the download, you can see how many times it has been requested under the downloads section of the Activity feed.
Note: This field only shows up if a bulk download is requested. The badge won't appear if there aren't any files requested.