Is sending nudes to a minor legal across state/country?

An adult of 23 from New York sent unsolicited nude pictures of himself to a 16 year old boy in Georgia, a 16 year old boy in Canada, and a 15 year old girl in Chicago. There is proof for the cases with the two boys of the adult sending the pictures and talking about sending the pictures, and flying over to have sex with one of the boys, but did not act upon the flying to the boy. There is no proof of the pictures being sent to the girl, only her talking about what happened to her.

What is everyone’s thoughts about this and do age of consent laws like this this carry over state to state? Because age of consent in NY is “In New York State, a person who is under age 16 but older than 13 years old can consent to sex with a person who is no more than 4 years older” and 16 in both Georgia and Canada. However, it is 17 in Chicago but can the adult be punished with no proof and only the word of her mouth?