Official SKE blog said it's a pic from before she joined SKE and it's just some friend. No problem at all. lol.
Oh, yeah, how stupid I was thinking about "bad things" between them. They are friends, just friends! Look at their faces, they can't lie

Now I am calm about it

P.S.
be honest I like Kumi and if that fag can care about her I am happy for them.