You need to choose your contacts better if you are genuinely concerned by this. They can already call you (and then, presumably, you'll just pick up) and then show you their dick.

Forget seeing random nudity, I don't even want to see a video of my husband's or kids' face on my phone unexpectedly.

Why should my phone be displaying something chosen by someone else unless I explicitly opted to engage with them (in this case by answering a video call)?

Plus, even if I did have contacts with a dick pic sense of humor, I'd much rather see a dick from them after I opt in to the call (so that I make sure I'm in an appropriate setting). Getting one randomly is insane.

Imagine if your husband or wife called you for some phone sex (say you are on a long trip) but you happen to be in the elevator with strangers on the way to your room. Brrring! No thanks.