FoundationSync 2.71 has been released for SharePoint Foundation 2013. This solution is designed to keep User and Group information in the User Information List up-to-date across all Site Collections on a SharePoint Foundation farm. The solution will also pull pictures from Active Directory or Exchange Server (tested with Exchange Server 2013, but should also be compatible with Exchange Server 2016).
The release is available from the FoundationSync GitHub repository. Please contribute by testing and reporting any issues you find, it only helps make for a better product!
Make sure to review the Wiki for documentation and additional settings not available through Central Administration.