Explicit content filter and/or other way to deal with inappropriate content sent by customers

It would be great if there was a way to deal with explicit image content sent by users. 

1. Have a filter in the system that detects inappropriate content in images
2. Have an option to automatically blur or hide images until you click on them
3. Hide images by default until you click on them

As we had problems with such content before, any method to detect or deal with such content would be much appreciated!