From the site: Everything in the hacks section is provided as-is unless you specifically have a contract with smugmug. They're not supported, endorsed, or guaranteed in any way. We'd love to fully support the API and other goodies with smugmug's AAA customer service, but we're just not there yet. Soon, we hope." Note they also offer a WebDAV interface for upload, as https://upload.smugmug.com/smugdav.mg.
The following is a list of SDKs from our SDK directory that matched your search term. Though your definition of an SDK may differ, in our world, we define SDKs as platform- specific tools for consuming existing APIs of the sort we list in our API directory. For example, the Ruby SDK for consuming the Twitter Ads API. If you think an SDK, API, or other asset is missing from our directory, be sure to check our guidelines for making contributions to ProgrammableWeb.