Yfrog, where the infamous pic of the supposed-Weiner-weiner was hosted, says their accounts were not compromised in any way.
After shutting down their services for a security review and then the statement, Morrissey at Hot Air explains it this way:
In other words, one cannot upload photos to Yfrog with just a username, as some had alleged. Nor has Yfrog’s e-mail upload system been hacked or compromised. One might suspect from the quick and categorical conclusion to their probe that they may have some fairly convincing evidence of the origin of Rep. Weiner’s tweet and photo. If Weiner really is interested in getting to the bottom of this, he could ask Yfrog to release that information to the public, or at least send investigators to retrieve it and find the culprits.
Of course, a failure to do either makes it pretty clear that Weiner or someone he granted access to the account uploaded the picture and sent the tweet.
The heat is on. The Other McCain says Weiner was missing from New York City’s Israel Day parade, with a graphic of a New York Post cover: HIDE THE WEINER – skips parades for backers. Actually, Weiner missed two high-profile parades. Related is WeinerGate a TweetDeck Disaster?