How can VZW do this without looking at the pic being sent first. It has to an all or nothing when it comes to pictures.
Now if they are coming from one particular number, place a block on that number in your online account
What's "offensive" is highly subjective, and Verizon doesn't know what may be "offensive" to you. As budone said, you can block messages if they are coming from a particular number, or block all picture messaging. Filtering out "offensive" is impossible.