Could they use a picture of your penis to prove guilt?

So I was just thinking about this, let's say someone was being accused of a crime but they didn't have 100% proof that this person did it. But, they had a picture of the guilty person's penis, could they make the accused person share a picture of his penis to prove his guilt? And bonus question, if he was innocent, could the accused person share the picture himself to prove his innocence?