In order to determine the content of the image (e.g. the possibility of inappropriate content in an image) you can utilize an API such as the Google Cloud Vision API which can filter images by content. The detection types are ranked over a probability distribution compared to the training data (ranging from Very Likely, Likely, Possible, Unlikely and Very Unlikely) over the following categories: Spoof (memes), Medical, Adult, and Violence.
Note: Cloud Vision API pricing exists outside the SMS Offering that LivePerson provides.
More info can be found here: https://cloud.google.com/vision/