I'd say the issue is probably one of judgment in having such pictures on your freely available to view Facebook account while running for parliament, rather than being snapped licking girl's breasts several years ago.
It is my impression that there are rather a lot of odd decisions taken by returning officers at this election. Another example is in Basingstoke where the new rules on candidate's names have been completely misinterpreted. The rules governing elections have never been static, so why are so many problems arising now? Has the status of Electoral Services been downgraded? Have they had disproportionate cuts in funding? Have training courses for EROs been axed? Or is it just that there is increasingly a culture of incompetence in this country?