Gravatar is recommended for a good quality profile image.
LinkedIn is recommended for basis of your LookPro profile information (it will make updating your LookPro profile easier).
We will add support for other social media services in upcoming BETA and RELEASE versions (see the planned schedule in Features & Roadmap). The aim is to cover all the most popular social media and cloud services to allow you and your employees to have spectacular LookPro profiles, but it is a lot of work to integrate and upkeep them all so we need to add them one by one. You can send us feedback what service to integrate next using the Contact Us form inside the LookPro service. We will listen to you.