The Congressman resigned because the one track mind media kept pounding and pounding on the ant hill, making it a molehill and then a lava-spewing volcano, with absolutely no basis. All he did was send naked photos to a few women far away who asked him for them. More women have come forward saying he did not send them photos than those who said he had.
Last time I looked, there was no law against a married person sending a naked photo to a consenting adult to whom they are not married. It's probably not illegal to do it using government equipment, but he says he did this on his own time and with his own computer.
He lied about it at first. BFD. What he does on his own time is his own business, as long as it's legal. If Bill Clinton didn't have to resign over a blowjob in the White House, no way does Weiner have to resign over sending photos to women he has never met.