In a moment that will probably go down in the annals of how not to handle a crisis, Rep. Anthony D. Weiner (D-N.Y.) insisted again on Wednesday that he was not the one who sent a suggestive photo from his Twitter account — but told NBC News that “I can’t say with certitude” whether the now-famous image was of his own crotch. Weiner gave a series of television interviews in an attempt to tamp down the furor that began over the weekend when a waist-down photograph of a man in his underwear appeared briefly on his page on the social networking site.