TAGGER.BIZ works with 3 Keyword-Providers:
Google Vision AI
Microsoft Vision
MyKeyworder.Com
To have an idea how this “keywording” works and what it is, check:
https://cloud.google.com/vision
https://azure.microsoft.com/en-us/services/cognitive-services/computer-vision/#features
http://mykeyworder.com/analyzeimageurl